661892377765 has 16 divisors (see below), whose sum is σ = 836815262400. Its totient is φ = 501200341632.

The previous prime is 661892377759. The next prime is 661892377777. The reversal of 661892377765 is 567773298166.

661892377765 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 661892377765 - 2³¹ = 659744894117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661892377765.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2978347 + ... + 3192856.

It is an arithmetic number, because the mean of its divisors is an integer number (52300953900).

Almost surely, 2^661892377765 is an apocalyptic number.

It is an amenable number.

661892377765 is a deficient number, since it is larger than the sum of its proper divisors (174922884635).

661892377765 is a wasteful number, since it uses less digits than its factorization.

661892377765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6172356.

The product of its digits is 160030080, while the sum is 67.

The spelling of 661892377765 in words is "six hundred sixty-one billion, eight hundred ninety-two million, three hundred seventy-seven thousand, seven hundred sixty-five".