21681154554 has 16 divisors (see below), whose sum is σ = 43973046720. Its totient is φ = 7125261920.

The previous prime is 21681154519. The next prime is 21681154613. The reversal of 21681154554 is 45545118612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25446939 + ... + 25447790.

It is an arithmetic number, because the mean of its divisors is an integer number (2748315420).

Almost surely, 2^21681154554 is an apocalyptic number.

21681154554 is an abundant number, since it is smaller than the sum of its proper divisors (22291892166).

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

21681154554 is a wasteful number, since it uses less digits than its factorization.

21681154554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50894805.

The product of its digits is 192000, while the sum is 42.

The spelling of 21681154554 in words is "twenty-one billion, six hundred eighty-one million, one hundred fifty-four thousand, five hundred fifty-four".