21317826808 has 32 divisors (see below), whose sum is σ = 40308572160. Its totient is φ = 10568970720.

The previous prime is 21317826769. The next prime is 21317826809. The reversal of 21317826808 is 80862871312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21317826809) 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, 2172393 + ... + 2182183.

It is an arithmetic number, because the mean of its divisors is an integer number (1259642880).

Almost surely, 2^21317826808 is an apocalyptic number.

It is an amenable number.

21317826808 is a deficient number, since it is larger than the sum of its proper divisors (18990745352).

21317826808 is a wasteful number, since it uses less digits than its factorization.

21317826808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12067 (or 12063 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 46.

The spelling of 21317826808 in words is "twenty-one billion, three hundred seventeen million, eight hundred twenty-six thousand, eight hundred eight".