21799192657 has 6 divisors (see below), whose sum is σ = 23961096194. Its totient is φ = 19817447760.

The previous prime is 21799192603. The next prime is 21799192663. The reversal of 21799192657 is 75629199712.

It can be written as a sum of positive squares in only one way, i.e., 21739733136 + 59459521 = 147444^2 + 7711^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21799192657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21799192697) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 90079188 + ... + 90079429.

Almost surely, 2^21799192657 is an apocalyptic number.

It is an amenable number.

21799192657 is a deficient number, since it is larger than the sum of its proper divisors (2161903537).

21799192657 is a wasteful number, since it uses less digits than its factorization.

21799192657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180158639 (or 180158628 counting only the distinct ones).

The product of its digits is 4286520, while the sum is 58.

The spelling of 21799192657 in words is "twenty-one billion, seven hundred ninety-nine million, one hundred ninety-two thousand, six hundred fifty-seven".