21585087 has 12 divisors (see below), whose sum is σ = 33012720. Its totient is φ = 13543488.

The previous prime is 21585071. The next prime is 21585107. The reversal of 21585087 is 78058512.

It is not a de Polignac number, because 21585087 - 2⁴ = 21585071 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21585587) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 70387 + ... + 70692.

It is an arithmetic number, because the mean of its divisors is an integer number (2751060).

Almost surely, 2^21585087 is an apocalyptic number.

21585087 is a deficient number, since it is larger than the sum of its proper divisors (11427633).

21585087 is a wasteful number, since it uses less digits than its factorization.

21585087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141102 (or 141099 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The square root of 21585087 is about 4645.9753550788. The cubic root of 21585087 is about 278.4312226551.

The spelling of 21585087 in words is "twenty-one million, five hundred eighty-five thousand, eighty-seven".