661554455166 has 64 divisors (see below), whose sum is σ = 1604750434560. Its totient is φ = 200348290080.

The previous prime is 661554455123. The next prime is 661554455171.

661554455166 is a `hidden beast` number, since 6 + 615 + 5 + 4 + 4 + 5 + 5 + 16 + 6 = 666.

661554455166 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 632205 + ... + 1312551.

It is an arithmetic number, because the mean of its divisors is an integer number (25074225540).

Almost surely, 2^661554455166 is an apocalyptic number.

661554455166 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

661554455166 is an abundant number, since it is smaller than the sum of its proper divisors (943195979394).

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

661554455166 is a wasteful number, since it uses less digits than its factorization.

661554455166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 682006 (or 682000 counting only the distinct ones).

The product of its digits is 12960000, while the sum is 54.

The spelling of 661554455166 in words is "six hundred sixty-one billion, five hundred fifty-four million, four hundred fifty-five thousand, one hundred sixty-six".