21708197131 has 8 divisors (see below), whose sum is σ = 21735751680. Its totient is φ = 21680661672.

The previous prime is 21708197123. The next prime is 21708197153. The reversal of 21708197131 is 13179180712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21708197131 - 2³ = 21708197123 is a prime.

It is a super-2 number, since 2×21708197131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21709197131) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 4861806 + ... + 4866268.

It is an arithmetic number, because the mean of its divisors is an integer number (2716968960).

Almost surely, 2^21708197131 is an apocalyptic number.

21708197131 is a deficient number, since it is larger than the sum of its proper divisors (27554549).

21708197131 is a wasteful number, since it uses less digits than its factorization.

21708197131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9545.

The product of its (nonzero) digits is 21168, while the sum is 40.

The spelling of 21708197131 in words is "twenty-one billion, seven hundred eight million, one hundred ninety-seven thousand, one hundred thirty-one".