21308697172 has 12 divisors (see below), whose sum is σ = 42617394400. Its totient is φ = 9132298776.

The previous prime is 21308697167. The next prime is 21308697191. The reversal of 21308697172 is 27179680312.

21308697172 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 380512422 + ... + 380512477.

Almost surely, 2^21308697172 is an apocalyptic number.

It is an amenable number.

21308697172 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21308697172 is a wasteful number, since it uses less digits than its factorization.

21308697172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 761024910 (or 761024908 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 46.

The spelling of 21308697172 in words is "twenty-one billion, three hundred eight million, six hundred ninety-seven thousand, one hundred seventy-two".