21038685 has 16 divisors (see below), whose sum is σ = 33796224. Its totient is φ = 11175872.

The previous prime is 21038683. The next prime is 21038687. The reversal of 21038685 is 58683012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21038683) and next prime (21038687).

It is a cyclic number.

It is not a de Polignac number, because 21038685 - 2¹ = 21038683 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21038683) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1279 + ... + 6611.

It is an arithmetic number, because the mean of its divisors is an integer number (2112264).

Almost surely, 2^21038685 is an apocalyptic number.

It is an amenable number.

21038685 is a deficient number, since it is larger than the sum of its proper divisors (12757539).

21038685 is a wasteful number, since it uses less digits than its factorization.

21038685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5604.

The product of its (nonzero) digits is 11520, while the sum is 33.

The square root of 21038685 is about 4586.7946324203. The cubic root of 21038685 is about 276.0617248001.

The spelling of 21038685 in words is "twenty-one million, thirty-eight thousand, six hundred eighty-five".