21079751 has 32 divisors (see below), whose sum is σ = 27724800. Its totient is φ = 15876000.

The previous prime is 21079727. The next prime is 21079769. The reversal of 21079751 is 15797012.

It is not a de Polignac number, because 21079751 - 2¹⁰ = 21078727 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 (21079651) 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, 139526 + ... + 139676.

It is an arithmetic number, because the mean of its divisors is an integer number (866400).

Almost surely, 2^21079751 is an apocalyptic number.

21079751 is a deficient number, since it is larger than the sum of its proper divisors (6645049).

21079751 is a wasteful number, since it uses less digits than its factorization.

21079751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220 (or 206 counting only the distinct ones).

The product of its (nonzero) digits is 4410, while the sum is 32.

The square root of 21079751 is about 4591.2689966936. The cubic root of 21079751 is about 276.2412256039.

The spelling of 21079751 in words is "twenty-one million, seventy-nine thousand, seven hundred fifty-one".