21656087 has 8 divisors (see below), whose sum is σ = 22678656. Its totient is φ = 20640312.

The previous prime is 21656081. The next prime is 21656093. The reversal of 21656087 is 78065612.

It is an interprime number because it is at equal distance from previous prime (21656081) and next prime (21656093).

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

It is a cyclic number.

It is not a de Polignac number, because 21656087 - 2⁶ = 21656023 is a prime.

It is a super-2 number, since 2×21656087² = 937972208303138, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21656081) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5528 + ... + 8594.

It is an arithmetic number, because the mean of its divisors is an integer number (2834832).

Almost surely, 2^21656087 is an apocalyptic number.

21656087 is a deficient number, since it is larger than the sum of its proper divisors (1022569).

21656087 is a wasteful number, since it uses less digits than its factorization.

21656087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3397.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 21656087 is about 4653.6101039945. The cubic root of 21656087 is about 278.7361705621.

The spelling of 21656087 in words is "twenty-one million, six hundred fifty-six thousand, eighty-seven".