21660561145012 has 48 divisors (see below), whose sum is σ = 41695258550400. Its totient is φ = 9800166499200.

The previous prime is 21660561145007. The next prime is 21660561145021. The reversal of 21660561145012 is 21054116506612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7613187 + ... + 10063882.

It is an arithmetic number, because the mean of its divisors is an integer number (868651219800).

Almost surely, 2^{21660561145012} is an apocalyptic number.

It is an amenable number.

21660561145012 is a deficient number, since it is larger than the sum of its proper divisors (20034697405388).

21660561145012 is a wasteful number, since it uses less digits than its factorization.

21660561145012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17677816 (or 17677814 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 40.

The spelling of 21660561145012 in words is "twenty-one trillion, six hundred sixty billion, five hundred sixty-one million, one hundred forty-five thousand, twelve".