21687880492 has 24 divisors (see below), whose sum is σ = 41572107360. Its totient is φ = 9854127360.

The previous prime is 21687880439. The next prime is 21687880517. The reversal of 21687880492 is 29408878612.

It is a happy number.

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, 5496984 + ... + 5500927.

It is an arithmetic number, because the mean of its divisors is an integer number (1732171140).

Almost surely, 2^21687880492 is an apocalyptic number.

It is an amenable number.

21687880492 is a deficient number, since it is larger than the sum of its proper divisors (19884226868).

21687880492 is a wasteful number, since it uses less digits than its factorization.

21687880492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10997961 (or 10997959 counting only the distinct ones).

The product of its (nonzero) digits is 3096576, while the sum is 55.

The spelling of 21687880492 in words is "twenty-one billion, six hundred eighty-seven million, eight hundred eighty thousand, four hundred ninety-two".