20143521 has 36 divisors (see below), whose sum is σ = 32065956. Its totient is φ = 12142080.

The previous prime is 20143517. The next prime is 20143523. The reversal of 20143521 is 12534102.

20143521 is a `hidden beast` number, since 2 + 0 + 143 + 521 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13838400 + 6305121 = 3720^2 + 2511^2 .

It is not a de Polignac number, because 20143521 - 2² = 20143517 is a prime.

It is a super-2 number, since 2×20143521² = 811522876554882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20143494 and 20143503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20143523) 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 35 ways as a sum of consecutive naturals, for example, 146965 + ... + 147101.

It is an arithmetic number, because the mean of its divisors is an integer number (890721).

Almost surely, 2^20143521 is an apocalyptic number.

It is an amenable number.

20143521 is a deficient number, since it is larger than the sum of its proper divisors (11922435).

20143521 is a wasteful number, since it uses less digits than its factorization.

20143521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20143521 is about 4488.1534064691. The cubic root of 20143521 is about 272.0895079196.

Adding to 20143521 its reverse (12534102), we get a palindrome (32677623).

The spelling of 20143521 in words is "twenty million, one hundred forty-three thousand, five hundred twenty-one".