21007456165 has 8 divisors (see below), whose sum is σ = 25274769408. Its totient is φ = 16762083600.

The previous prime is 21007456159. The next prime is 21007456201. The reversal of 21007456165 is 56165470012.

It is a happy number.

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

It is not a de Polignac number, because 21007456165 - 2⁵ = 21007456133 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 5483061 + ... + 5486890.

It is an arithmetic number, because the mean of its divisors is an integer number (3159346176).

Almost surely, 2^21007456165 is an apocalyptic number.

It is an amenable number.

21007456165 is a deficient number, since it is larger than the sum of its proper divisors (4267313243).

21007456165 is a wasteful number, since it uses less digits than its factorization.

21007456165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10970339.

The product of its (nonzero) digits is 50400, while the sum is 37.

The spelling of 21007456165 in words is "twenty-one billion, seven million, four hundred fifty-six thousand, one hundred sixty-five".