21976798638 has 16 divisors (see below), whose sum is σ = 43955458560. Its totient is φ = 7325289336.

The previous prime is 21976798633. The next prime is 21976798673. The reversal of 21976798638 is 83689767912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21976798633) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111331 + ... + 237377.

It is an arithmetic number, because the mean of its divisors is an integer number (2747216160).

Almost surely, 2^21976798638 is an apocalyptic number.

21976798638 is an abundant number, since it is smaller than the sum of its proper divisors (21978659922).

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

21976798638 is a wasteful number, since it uses less digits than its factorization.

21976798638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155111.

The product of its digits is 54867456, while the sum is 66.

The spelling of 21976798638 in words is "twenty-one billion, nine hundred seventy-six million, seven hundred ninety-eight thousand, six hundred thirty-eight".