21320956 has 6 divisors (see below), whose sum is σ = 37311680. Its totient is φ = 10660476.

The previous prime is 21320947. The next prime is 21320969. The reversal of 21320956 is 65902312.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2665116 + ... + 2665123.

Almost surely, 2^21320956 is an apocalyptic number.

It is an amenable number.

21320956 is a deficient number, since it is larger than the sum of its proper divisors (15990724).

21320956 is a wasteful number, since it uses less digits than its factorization.

21320956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5330243 (or 5330241 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 21320956 is about 4617.4620734772. The cubic root of 21320956 is about 277.2908620911.

The spelling of 21320956 in words is "twenty-one million, three hundred twenty thousand, nine hundred fifty-six".