21108779752 has 64 divisors (see below), whose sum is σ = 42425208000. Its totient is φ = 9816205824.

The previous prime is 21108779677. The next prime is 21108779761. The reversal of 21108779752 is 25797780112.

It is a junction number, because it is equal to n+sod(n) for n = 21108779696 and 21108779705.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10697838 + ... + 10699810.

It is an arithmetic number, because the mean of its divisors is an integer number (662893875).

Almost surely, 2^21108779752 is an apocalyptic number.

It is an amenable number.

21108779752 is an abundant number, since it is smaller than the sum of its proper divisors (21316428248).

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

21108779752 is a wasteful number, since it uses less digits than its factorization.

21108779752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3250 (or 3246 counting only the distinct ones).

The product of its (nonzero) digits is 493920, while the sum is 49.

The spelling of 21108779752 in words is "twenty-one billion, one hundred eight million, seven hundred seventy-nine thousand, seven hundred fifty-two".