21156937 has 8 divisors (see below), whose sum is σ = 22341600. Its totient is φ = 19979424.

The previous prime is 21156931. The next prime is 21156953. The reversal of 21156937 is 73965112.

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 21156937 - 2³ = 21156929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21156931) 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, 4989 + ... + 8197.

It is an arithmetic number, because the mean of its divisors is an integer number (2792700).

Almost surely, 2^21156937 is an apocalyptic number.

It is an amenable number.

21156937 is a deficient number, since it is larger than the sum of its proper divisors (1184663).

21156937 is a wasteful number, since it uses less digits than its factorization.

21156937 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3575.

The product of its digits is 11340, while the sum is 34.

The square root of 21156937 is about 4599.6670531681. The cubic root of 21156937 is about 276.5779782181.

The spelling of 21156937 in words is "twenty-one million, one hundred fifty-six thousand, nine hundred thirty-seven".