661357954178 has 16 divisors (see below), whose sum is σ = 992811193920. Its totient is φ = 330420951600.

The previous prime is 661357954141. The next prime is 661357954237. The reversal of 661357954178 is 871459753166.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 661357954178.

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, 38938448 + ... + 38955428.

It is an arithmetic number, because the mean of its divisors is an integer number (62050699620).

Almost surely, 2^661357954178 is an apocalyptic number.

661357954178 is a deficient number, since it is larger than the sum of its proper divisors (331453239742).

661357954178 is a wasteful number, since it uses less digits than its factorization.

661357954178 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31033.

The product of its digits is 38102400, while the sum is 62.

The spelling of 661357954178 in words is "six hundred sixty-one billion, three hundred fifty-seven million, nine hundred fifty-four thousand, one hundred seventy-eight".