21117176645 has 32 divisors (see below), whose sum is σ = 27684115200. Its totient is φ = 15413837824.

The previous prime is 21117176629. The next prime is 21117176651. The reversal of 21117176645 is 54667171112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21117176645 - 2⁴ = 21117176629 is a prime.

It is a super-2 number, since 2×21117176645² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 238661 + ... + 314949.

It is an arithmetic number, because the mean of its divisors is an integer number (865128600).

Almost surely, 2^21117176645 is an apocalyptic number.

It is an amenable number.

21117176645 is a deficient number, since it is larger than the sum of its proper divisors (6566938555).

21117176645 is a wasteful number, since it uses less digits than its factorization.

21117176645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76429.

The product of its digits is 70560, while the sum is 41.

The spelling of 21117176645 in words is "twenty-one billion, one hundred seventeen million, one hundred seventy-six thousand, six hundred forty-five".