21163760465 has 8 divisors (see below), whose sum is σ = 25399375848. Its totient is φ = 16929099520.

The previous prime is 21163760399. The next prime is 21163760491. The reversal of 21163760465 is 56406736112.

It can be written as a sum of positive squares in 4 ways, for example, as 11090827969 + 10072932496 = 105313^2 + 100364^2 .

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

It is not a de Polignac number, because 21163760465 - 2²² = 21159566161 is a prime.

It is a Duffinian 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, 188882 + ... + 279291.

It is an arithmetic number, because the mean of its divisors is an integer number (3174921981).

Almost surely, 2^21163760465 is an apocalyptic number.

It is an amenable number.

21163760465 is a deficient number, since it is larger than the sum of its proper divisors (4235615383).

21163760465 is an equidigital number, since it uses as much as digits as its factorization.

21163760465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477219.

The product of its (nonzero) digits is 181440, while the sum is 41.

The spelling of 21163760465 in words is "twenty-one billion, one hundred sixty-three million, seven hundred sixty thousand, four hundred sixty-five".