18961518977208 has 48 divisors (see below), whose sum is σ = 51357393968400. Its totient is φ = 6320102624640.

The previous prime is 18961518977207. The next prime is 18961518977231. The reversal of 18961518977208 is 80277981516981.

18961518977208 is a `hidden beast` number, since 1 + 89 + 6 + 1 + 518 + 9 + 7 + 7 + 20 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18961518977207) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7274293 + ... + 9530916.

It is an arithmetic number, because the mean of its divisors is an integer number (1069945707675).

Almost surely, 2^{18961518977208} is an apocalyptic number.

18961518977208 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

18961518977208 is an abundant number, since it is smaller than the sum of its proper divisors (32395874991192).

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

18961518977208 is a wasteful number, since it uses less digits than its factorization.

18961518977208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16820892 (or 16820885 counting only the distinct ones).

The product of its (nonzero) digits is 121927680, while the sum is 72.

The spelling of 18961518977208 in words is "eighteen trillion, nine hundred sixty-one billion, five hundred eighteen million, nine hundred seventy-seven thousand, two hundred eight".