21656153 has 4 divisors (see below), whose sum is σ = 21769728. Its totient is φ = 21542580.

The previous prime is 21656149. The next prime is 21656161. The reversal of 21656153 is 35165612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21656153 - 2² = 21656149 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21656183) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56501 + ... + 56882.

It is an arithmetic number, because the mean of its divisors is an integer number (5442432).

Almost surely, 2^21656153 is an apocalyptic number.

It is an amenable number.

21656153 is a deficient number, since it is larger than the sum of its proper divisors (113575).

21656153 is a wasteful number, since it uses less digits than its factorization.

21656153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113574.

The product of its digits is 5400, while the sum is 29.

The square root of 21656153 is about 4653.6171952579. The cubic root of 21656153 is about 278.7364537245.

The spelling of 21656153 in words is "twenty-one million, six hundred fifty-six thousand, one hundred fifty-three".