21109993716 has 48 divisors (see below), whose sum is σ = 56630439936. Its totient is φ = 5995306464.

The previous prime is 21109993669. The next prime is 21109993717. The reversal of 21109993716 is 61739990112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21109993717) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 738396 + ... + 766451.

It is an arithmetic number, because the mean of its divisors is an integer number (1179800832).

Almost surely, 2^21109993716 is an apocalyptic number.

It is an amenable number.

21109993716 is an abundant number, since it is smaller than the sum of its proper divisors (35520446220).

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

21109993716 is a wasteful number, since it uses less digits than its factorization.

21109993716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1505028 (or 1505026 counting only the distinct ones).

The product of its (nonzero) digits is 183708, while the sum is 48.

The spelling of 21109993716 in words is "twenty-one billion, one hundred nine million, nine hundred ninety-three thousand, seven hundred sixteen".