21316757 has 16 divisors (see below), whose sum is σ = 26849664. Its totient is φ = 16440000.

The previous prime is 21316753. The next prime is 21316783. The reversal of 21316757 is 75761312.

It is a cyclic number.

It is not a de Polignac number, because 21316757 - 2² = 21316753 is a prime.

It is a Duffinian number.

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 15 ways as a sum of consecutive naturals, for example, 6407 + ... + 9147.

It is an arithmetic number, because the mean of its divisors is an integer number (1678104).

Almost surely, 2^21316757 is an apocalyptic number.

It is an amenable number.

21316757 is a deficient number, since it is larger than the sum of its proper divisors (5532907).

21316757 is a wasteful number, since it uses less digits than its factorization.

21316757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2860.

The product of its digits is 8820, while the sum is 32.

The square root of 21316757 is about 4617.0073640834. The cubic root of 21316757 is about 277.2726574544.

It can be divided in two parts, 2131 and 6757, that added together give a palindrome (8888).

The spelling of 21316757 in words is "twenty-one million, three hundred sixteen thousand, seven hundred fifty-seven".