661785414912 has 54 divisors (see below), whose sum is σ = 1908090506322. Its totient is φ = 220595137536.

The previous prime is 661785414881. The next prime is 661785414937. The reversal of 661785414912 is 219414587166.

661785414912 is a `hidden beast` number, since 6 + 6 + 1 + 7 + 8 + 541 + 4 + 91 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 604139325696 + 57646089216 = 777264^2 + 240096^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 143614323 + ... + 143618930.

Almost surely, 2^661785414912 is an apocalyptic number.

It is an amenable number.

661785414912 is an abundant number, since it is smaller than the sum of its proper divisors (1246305091410).

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

661785414912 is a wasteful number, since it uses less digits than its factorization.

661785414912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287233275 (or 287233258 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The spelling of 661785414912 in words is "six hundred sixty-one billion, seven hundred eighty-five million, four hundred fourteen thousand, nine hundred twelve".