661556151651612 has 24 divisors (see below), whose sum is σ = 1764149737737856. Its totient is φ = 189016043329008.

The previous prime is 661556151651607. The next prime is 661556151651631. The reversal of 661556151651612 is 216156151655166.

661556151651612 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

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, 3937834235938 + ... + 3937834236105.

Almost surely, 2^{661556151651612} is an apocalyptic number.

It is an amenable number.

661556151651612 is an abundant number, since it is smaller than the sum of its proper divisors (1102593586086244).

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

661556151651612 is a wasteful number, since it uses less digits than its factorization.

661556151651612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7875668472057 (or 7875668472055 counting only the distinct ones).

The product of its digits is 9720000, while the sum is 57.

The spelling of 661556151651612 in words is "six hundred sixty-one trillion, five hundred fifty-six billion, one hundred fifty-one million, six hundred fifty-one thousand, six hundred twelve".