21089687916 has 24 divisors (see below), whose sum is σ = 53682842304. Its totient is φ = 6390814480.

The previous prime is 21089687897. The next prime is 21089687923. The reversal of 21089687916 is 61978698012.

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, 79885050 + ... + 79885313.

It is an arithmetic number, because the mean of its divisors is an integer number (2236785096).

Almost surely, 2^21089687916 is an apocalyptic number.

It is an amenable number.

21089687916 is an abundant number, since it is smaller than the sum of its proper divisors (32593154388).

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

21089687916 is a wasteful number, since it uses less digits than its factorization.

21089687916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159770381 (or 159770379 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 57.

The spelling of 21089687916 in words is "twenty-one billion, eighty-nine million, six hundred eighty-seven thousand, nine hundred sixteen".