21356772 has 24 divisors (see below), whose sum is σ = 50301216. Its totient is φ = 7051968.

The previous prime is 21356759. The next prime is 21356773. The reversal of 21356772 is 27765312.

It is a super-2 number, since 2×21356772² = 912223420519968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21356773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7033 + ... + 9600.

It is an arithmetic number, because the mean of its divisors is an integer number (2095884).

Almost surely, 2^21356772 is an apocalyptic number.

It is an amenable number.

21356772 is an abundant number, since it is smaller than the sum of its proper divisors (28944444).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21356772 is a wasteful number, since it uses less digits than its factorization.

21356772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16747 (or 16745 counting only the distinct ones).

The product of its digits is 17640, while the sum is 33.

The square root of 21356772 is about 4621.3387670674. The cubic root of 21356772 is about 277.4460442131.

The spelling of 21356772 in words is "twenty-one million, three hundred fifty-six thousand, seven hundred seventy-two".