21791695858 has 16 divisors (see below), whose sum is σ = 33041775960. Its totient is φ = 10778150656.

The previous prime is 21791695847. The next prime is 21791695867. The reversal of 21791695858 is 85859619712.

It can be written as a sum of positive squares in 4 ways, for example, as 13368678129 + 8423017729 = 115623^2 + 91777^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21791695796 and 21791695805.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20316 + ... + 209752.

Almost surely, 2^21791695858 is an apocalyptic number.

21791695858 is a deficient number, since it is larger than the sum of its proper divisors (11250080102).

21791695858 is a wasteful number, since it uses less digits than its factorization.

21791695858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190061.

The product of its digits is 10886400, while the sum is 61.

The spelling of 21791695858 in words is "twenty-one billion, seven hundred ninety-one million, six hundred ninety-five thousand, eight hundred fifty-eight".