21317883891 has 32 divisors (see below), whose sum is σ = 31337280000. Its totient is φ = 12830450688.

The previous prime is 21317883887. The next prime is 21317883893. The reversal of 21317883891 is 19838871312.

It is not a de Polignac number, because 21317883891 - 2² = 21317883887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21317883893) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 322435 + ... + 382883.

It is an arithmetic number, because the mean of its divisors is an integer number (979290000).

Almost surely, 2^21317883891 is an apocalyptic number.

21317883891 is a deficient number, since it is larger than the sum of its proper divisors (10019396109).

21317883891 is a wasteful number, since it uses less digits than its factorization.

21317883891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60763.

The product of its digits is 580608, while the sum is 51.

The spelling of 21317883891 in words is "twenty-one billion, three hundred seventeen million, eight hundred eighty-three thousand, eight hundred ninety-one".