21442881636 has 72 divisors (see below), whose sum is σ = 59440163328. Its totient is φ = 6463800000.

The previous prime is 21442881631. The next prime is 21442881671. The reversal of 21442881636 is 63618824412.

21442881636 is a `hidden beast` number, since 2 + 1 + 4 + 4 + 2 + 8 + 8 + 1 + 636 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21442881591 and 21442881600.

It is not an unprimeable number, because it can be changed into a prime (21442881631) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 66115 + ... + 217386.

It is an arithmetic number, because the mean of its divisors is an integer number (825557824).

Almost surely, 2^21442881636 is an apocalyptic number.

It is an amenable number.

21442881636 is an abundant number, since it is smaller than the sum of its proper divisors (37997281692).

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

21442881636 is a wasteful number, since it uses less digits than its factorization.

21442881636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283713 (or 283708 counting only the distinct ones).

The product of its digits is 442368, while the sum is 45.

The spelling of 21442881636 in words is "twenty-one billion, four hundred forty-two million, eight hundred eighty-one thousand, six hundred thirty-six".