21556085 has 8 divisors (see below), whose sum is σ = 27389016. Its totient is φ = 16230400.

The previous prime is 21556061. The next prime is 21556103. The reversal of 21556085 is 58065512.

It can be written as a sum of positive squares in 4 ways, for example, as 386884 + 21169201 = 622^2 + 4601^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21556085 - 2⁶ = 21556021 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126716 + ... + 126885.

It is an arithmetic number, because the mean of its divisors is an integer number (3423627).

Almost surely, 2^21556085 is an apocalyptic number.

It is an amenable number.

21556085 is a deficient number, since it is larger than the sum of its proper divisors (5832931).

21556085 is a wasteful number, since it uses less digits than its factorization.

21556085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253623.

The product of its (nonzero) digits is 12000, while the sum is 32.

The square root of 21556085 is about 4642.8531098884. The cubic root of 21556085 is about 278.3064655082.

The spelling of 21556085 in words is "twenty-one million, five hundred fifty-six thousand, eighty-five".