21316756 has 24 divisors (see below), whose sum is σ = 38658816. Its totient is φ = 10278240.

The previous prime is 21316753. The next prime is 21316783. The reversal of 21316756 is 65761312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21316751) 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, 12550 + ... + 14146.

It is an arithmetic number, because the mean of its divisors is an integer number (1610784).

Almost surely, 2^21316756 is an apocalyptic number.

It is an amenable number.

21316756 is a deficient number, since it is larger than the sum of its proper divisors (17342060).

21316756 is a wasteful number, since it uses less digits than its factorization.

21316756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1719 (or 1717 counting only the distinct ones).

The product of its digits is 7560, while the sum is 31.

The square root of 21316756 is about 4617.0072557881. The cubic root of 21316756 is about 277.2726531186.

The spelling of 21316756 in words is "twenty-one million, three hundred sixteen thousand, seven hundred fifty-six".