220531501 has 4 divisors (see below), whose sum is σ = 220563004. Its totient is φ = 220500000.

The previous prime is 220531483. The next prime is 220531523. The reversal of 220531501 is 105135022.

220531501 is a nontrivial binomial coefficient, being equal to C(21002, 2).

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 105135022 = 2 ⋅52567511.

It can be written as a sum of positive squares in 2 ways, for example, as 56025225 + 164506276 = 7485^2 + 12826^2 .

It is a 3-Lehmer number, since φ(220531501) divides (220531501-1)³.

It is a cyclic number.

It is not a de Polignac number, because 220531501 - 2⁵ = 220531469 is a prime.

It is a deceptive number, since it divides R_220531500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220531561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1 + ... + 21001.

It is an arithmetic number, because the mean of its divisors is an integer number (55140751).

It is a Poulet number, since it divides 2^220531500-1.

Almost surely, 2^220531501 is an apocalyptic number.

220531501 is the 21001-st triangular number and also the 10501-st hexagonal number.

220531501 is the 7001-st centered nonagonal number.

It is an amenable number.

220531501 is a deficient number, since it is larger than the sum of its proper divisors (31503).

220531501 is a wasteful number, since it uses less digits than its factorization.

220531501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31502.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 220531501 is about 14850.3030608806. The cubic root of 220531501 is about 604.1668298205.

Adding to 220531501 its reverse (105135022), we get a palindrome (325666523).

The spelling of 220531501 in words is "two hundred twenty million, five hundred thirty-one thousand, five hundred one".