21291479056 has 15 divisors (see below), whose sum is σ = 41253371551. Its totient is φ = 10645447696.

The previous prime is 21291479029. The next prime is 21291479089. The reversal of 21291479056 is 65097419212.

The square root of 21291479056 is 145916.

It is a perfect power (a square), and thus also a powerful number.

It is a super-2 number, since 2×21291479056² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21291478997 and 21291479015.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 565425 + ... + 601903.

Almost surely, 2^21291479056 is an apocalyptic number.

21291479056 is the 145916-th square number.

It is an amenable number.

21291479056 is a deficient number, since it is larger than the sum of its proper divisors (19961892495).

21291479056 is an frugal number, since it uses more digits than its factorization.

21291479056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72966 (or 36481 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 46.

The spelling of 21291479056 in words is "twenty-one billion, two hundred ninety-one million, four hundred seventy-nine thousand, fifty-six".