21163660265 has 8 divisors (see below), whose sum is σ = 27705155328. Its totient is φ = 15391752880.

The previous prime is 21163660261. The next prime is 21163660267. The reversal of 21163660265 is 56206636112.

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 21163660265 - 2² = 21163660261 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21163660261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 192396857 + ... + 192396966.

It is an arithmetic number, because the mean of its divisors is an integer number (3463144416).

Almost surely, 2^21163660265 is an apocalyptic number.

It is an amenable number.

21163660265 is a deficient number, since it is larger than the sum of its proper divisors (6541495063).

21163660265 is a wasteful number, since it uses less digits than its factorization.

21163660265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384793839.

The product of its (nonzero) digits is 77760, while the sum is 38.

The spelling of 21163660265 in words is "twenty-one billion, one hundred sixty-three million, six hundred sixty thousand, two hundred sixty-five".