21197827608 has 16 divisors (see below), whose sum is σ = 52994569080. Its totient is φ = 7065942528.

The previous prime is 21197827597. The next prime is 21197827661. The reversal of 21197827608 is 80672879112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 441621385 + ... + 441621432.

Almost surely, 2^21197827608 is an apocalyptic number.

It is an amenable number.

21197827608 is an abundant number, since it is smaller than the sum of its proper divisors (31796741472).

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

21197827608 is a wasteful number, since it uses less digits than its factorization.

21197827608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 883242826 (or 883242822 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 51.

The spelling of 21197827608 in words is "twenty-one billion, one hundred ninety-seven million, eight hundred twenty-seven thousand, six hundred eight".