21156933 has 32 divisors (see below), whose sum is σ = 33654016. Its totient is φ = 11570688.

The previous prime is 21156931. The next prime is 21156953. The reversal of 21156933 is 33965112.

It is not a de Polignac number, because 21156933 - 2¹ = 21156931 is a prime.

It is a super-3 number, since 3×21156933³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21156933.

It is a congruent 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 31 ways as a sum of consecutive naturals, for example, 56535 + ... + 56907.

It is an arithmetic number, because the mean of its divisors is an integer number (1051688).

Almost surely, 2^21156933 is an apocalyptic number.

It is an amenable number.

21156933 is a deficient number, since it is larger than the sum of its proper divisors (12497083).

21156933 is a wasteful number, since it uses less digits than its factorization.

21156933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493.

The product of its digits is 4860, while the sum is 30.

The square root of 21156933 is about 4599.6666183540. Note that the first 4 decimals coincide. The cubic root of 21156933 is about 276.5779607878.

The spelling of 21156933 in words is "twenty-one million, one hundred fifty-six thousand, nine hundred thirty-three".