21097578660 has 48 divisors (see below), whose sum is σ = 59202560256. Its totient is φ = 5613702912.

The previous prime is 21097578659. The next prime is 21097578679. The reversal of 21097578660 is 6687579012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 357292 + ... + 412131.

It is an arithmetic number, because the mean of its divisors is an integer number (1233386672).

Almost surely, 2^21097578660 is an apocalyptic number.

21097578660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21097578660 is an abundant number, since it is smaller than the sum of its proper divisors (38104981596).

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

21097578660 is a wasteful number, since it uses less digits than its factorization.

21097578660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769892 (or 769890 counting only the distinct ones).

The product of its (nonzero) digits is 1270080, while the sum is 51.

The spelling of 21097578660 in words is "twenty-one billion, ninety-seven million, five hundred seventy-eight thousand, six hundred sixty".