21156179465 has 8 divisors (see below), whose sum is σ = 26880792840. Its totient is φ = 15929358592.

The previous prime is 21156179453. The next prime is 21156179477. The reversal of 21156179465 is 56497165112.

It is an interprime number because it is at equal distance from previous prime (21156179453) and next prime (21156179477).

It can be written as a sum of positive squares in 4 ways, for example, as 1426044169 + 19730135296 = 37763^2 + 140464^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21156179465 - 2⁴ = 21156179449 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124448030 + ... + 124448199.

It is an arithmetic number, because the mean of its divisors is an integer number (3360099105).

Almost surely, 2^21156179465 is an apocalyptic number.

It is an amenable number.

21156179465 is a deficient number, since it is larger than the sum of its proper divisors (5724613375).

21156179465 is a wasteful number, since it uses less digits than its factorization.

21156179465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248896251.

The product of its digits is 453600, while the sum is 47.

The spelling of 21156179465 in words is "twenty-one billion, one hundred fifty-six million, one hundred seventy-nine thousand, four hundred sixty-five".