221501389 has 4 divisors (see below), whose sum is σ = 221665500. Its totient is φ = 221337280.

The previous prime is 221501387. The next prime is 221501429. The reversal of 221501389 is 983105122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 983105122 = 2 ⋅491552561.

It can be written as a sum of positive squares in 2 ways, for example, as 112466025 + 109035364 = 10605^2 + 10442^2 .

It is a cyclic number.

It is not a de Polignac number, because 221501389 - 2¹ = 221501387 is a prime.

It is a super-3 number, since 3×221501389³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221501389.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221501387) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80014 + ... + 82735.

It is an arithmetic number, because the mean of its divisors is an integer number (55416375).

Almost surely, 2^221501389 is an apocalyptic number.

It is an amenable number.

221501389 is a deficient number, since it is larger than the sum of its proper divisors (164111).

221501389 is a wasteful number, since it uses less digits than its factorization.

221501389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164110.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 221501389 is about 14882.9227304317. The cubic root of 221501389 is about 605.0512344198.

The spelling of 221501389 in words is "two hundred twenty-one million, five hundred one thousand, three hundred eighty-nine".