18721380656456 has 32 divisors (see below), whose sum is σ = 36969948926400. Its totient is φ = 8863257090240.

The previous prime is 18721380656417. The next prime is 18721380656471. The reversal of 18721380656456 is 65465608312781.

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, 32808740 + ... + 33374483.

It is an arithmetic number, because the mean of its divisors is an integer number (1155310903950).

Almost surely, 2^{18721380656456} is an apocalyptic number.

It is an amenable number.

18721380656456 is a deficient number, since it is larger than the sum of its proper divisors (18248568269944).

18721380656456 is a wasteful number, since it uses less digits than its factorization.

18721380656456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66185109 (or 66185105 counting only the distinct ones).

The product of its (nonzero) digits is 58060800, while the sum is 62.

The spelling of 18721380656456 in words is "eighteen trillion, seven hundred twenty-one billion, three hundred eighty million, six hundred fifty-six thousand, four hundred fifty-six".