21617715670 has 16 divisors (see below), whose sum is σ = 38914515360. Its totient is φ = 8646502464.

The previous prime is 21617715653. The next prime is 21617715673. The reversal of 21617715670 is 7651771612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21617715673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102679 + ... + 231901.

It is an arithmetic number, because the mean of its divisors is an integer number (2432157210).

Almost surely, 2^21617715670 is an apocalyptic number.

21617715670 is a deficient number, since it is larger than the sum of its proper divisors (17296799690).

21617715670 is a wasteful number, since it uses less digits than its factorization.

21617715670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145959.

The product of its (nonzero) digits is 123480, while the sum is 43.

The spelling of 21617715670 in words is "twenty-one billion, six hundred seventeen million, seven hundred fifteen thousand, six hundred seventy".