21542104644 has 24 divisors (see below), whose sum is σ = 51334378368. Its totient is φ = 7027920480.

The previous prime is 21542104621. The next prime is 21542104669. The reversal of 21542104644 is 44640124512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19097047 + ... + 19098174.

It is an arithmetic number, because the mean of its divisors is an integer number (2138932432).

Almost surely, 2^21542104644 is an apocalyptic number.

It is an amenable number.

21542104644 is an abundant number, since it is smaller than the sum of its proper divisors (29792273724).

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

21542104644 is a wasteful number, since it uses less digits than its factorization.

21542104644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38195275 (or 38195273 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 33.

The spelling of 21542104644 in words is "twenty-one billion, five hundred forty-two million, one hundred four thousand, six hundred forty-four".