21156938 has 8 divisors (see below), whose sum is σ = 34620480. Its totient is φ = 9616780.

The previous prime is 21156931. The next prime is 21156953. The reversal of 21156938 is 83965112.

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

It is a junction number, because it is equal to n+sod(n) for n = 21156898 and 21156907.

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 3 ways as a sum of consecutive naturals, for example, 480818 + ... + 480861.

It is an arithmetic number, because the mean of its divisors is an integer number (4327560).

Almost surely, 2^21156938 is an apocalyptic number.

21156938 is a deficient number, since it is larger than the sum of its proper divisors (13463542).

21156938 is a wasteful number, since it uses less digits than its factorization.

21156938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 961692.

The product of its digits is 12960, while the sum is 35.

The square root of 21156938 is about 4599.6671618716. The cubic root of 21156938 is about 276.5779825756.

The spelling of 21156938 in words is "twenty-one million, one hundred fifty-six thousand, nine hundred thirty-eight".