20887665 has 16 divisors (see below), whose sum is σ = 33524928. Its totient is φ = 11105216.

The previous prime is 20887663. The next prime is 20887667. The reversal of 20887665 is 56678802.

It is an interprime number because it is at equal distance from previous prime (20887663) and next prime (20887667).

It is a cyclic number.

It is not a de Polignac number, because 20887665 - 2¹ = 20887663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20887663) 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, 3199 + ... + 7211.

It is an arithmetic number, because the mean of its divisors is an integer number (2095308).

Almost surely, 2^20887665 is an apocalyptic number.

It is an amenable number.

20887665 is a deficient number, since it is larger than the sum of its proper divisors (12637263).

20887665 is a wasteful number, since it uses less digits than its factorization.

20887665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4368.

The product of its (nonzero) digits is 161280, while the sum is 42.

The square root of 20887665 is about 4570.3025063993. The cubic root of 20887665 is about 275.3995953856.

The spelling of 20887665 in words is "twenty million, eight hundred eighty-seven thousand, six hundred sixty-five".