21158970538 has 16 divisors (see below), whose sum is σ = 32101704000. Its totient is φ = 10458451872.

The previous prime is 21158970523. The next prime is 21158970557. The reversal of 21158970538 is 83507985112.

It is a junction number, because it is equal to n+sod(n) for n = 21158970491 and 21158970500.

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, 1169203 + ... + 1187161.

It is an arithmetic number, because the mean of its divisors is an integer number (2006356500).

Almost surely, 2^21158970538 is an apocalyptic number.

21158970538 is a deficient number, since it is larger than the sum of its proper divisors (10942733462).

21158970538 is a wasteful number, since it uses less digits than its factorization.

21158970538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24669.

The product of its (nonzero) digits is 604800, while the sum is 49.

The spelling of 21158970538 in words is "twenty-one billion, one hundred fifty-eight million, nine hundred seventy thousand, five hundred thirty-eight".