21557085 has 16 divisors (see below), whose sum is σ = 37627200. Its totient is φ = 10451840.

The previous prime is 21557057. The next prime is 21557099. The reversal of 21557085 is 58075512.

It is a happy number.

It is not a de Polignac number, because 21557085 - 2⁹ = 21556573 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 Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65160 + ... + 65489.

It is an arithmetic number, because the mean of its divisors is an integer number (2351700).

Almost surely, 2^21557085 is an apocalyptic number.

It is an amenable number.

21557085 is a deficient number, since it is larger than the sum of its proper divisors (16070115).

21557085 is a wasteful number, since it uses less digits than its factorization.

21557085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130668.

The product of its (nonzero) digits is 14000, while the sum is 33.

The square root of 21557085 is about 4642.9608010406. The cubic root of 21557085 is about 278.3107690442.

The spelling of 21557085 in words is "twenty-one million, five hundred fifty-seven thousand, eighty-five".