21675637 has 16 divisors (see below), whose sum is σ = 24024960. Its totient is φ = 19464192.

The previous prime is 21675613. The next prime is 21675649. The reversal of 21675637 is 73657612.

It is a cyclic number.

It is not a de Polignac number, because 21675637 - 2¹⁵ = 21642869 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21675596 and 21675605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21675337) 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, 84213 + ... + 84469.

It is an arithmetic number, because the mean of its divisors is an integer number (1501560).

Almost surely, 2^21675637 is an apocalyptic number.

It is an amenable number.

21675637 is a deficient number, since it is larger than the sum of its proper divisors (2349323).

21675637 is a wasteful number, since it uses less digits than its factorization.

21675637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 492.

The product of its digits is 52920, while the sum is 37.

The square root of 21675637 is about 4655.7101499127. The cubic root of 21675637 is about 278.8200215547.

The spelling of 21675637 in words is "twenty-one million, six hundred seventy-five thousand, six hundred thirty-seven".