21581606855512 has 32 divisors (see below), whose sum is σ = 44436541536000. Its totient is φ = 9744855588000.

The previous prime is 21581606855503. The next prime is 21581606855531. The reversal of 21581606855512 is 21555860618512.

It is a congruent number.

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, 812058012 + ... + 812084587.

It is an arithmetic number, because the mean of its divisors is an integer number (1388641923000).

Almost surely, 2^{21581606855512} is an apocalyptic number.

21581606855512 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21581606855512 is an abundant number, since it is smaller than the sum of its proper divisors (22854934680488).

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

21581606855512 is a wasteful number, since it uses less digits than its factorization.

21581606855512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1624142767 (or 1624142763 counting only the distinct ones).

The product of its (nonzero) digits is 5760000, while the sum is 55.

The spelling of 21581606855512 in words is "twenty-one trillion, five hundred eighty-one billion, six hundred six million, eight hundred fifty-five thousand, five hundred twelve".