661873777795 has 16 divisors (see below), whose sum is σ = 851101201440. Its totient is φ = 492347774464.

The previous prime is 661873777709. The next prime is 661873777801. The reversal of 661873777795 is 597777378166.

It is not a de Polignac number, because 661873777795 - 2¹¹ = 661873775747 is a prime.

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, 46901080 + ... + 46915189.

It is an arithmetic number, because the mean of its divisors is an integer number (53193825090).

Almost surely, 2^661873777795 is an apocalyptic number.

661873777795 is a deficient number, since it is larger than the sum of its proper divisors (189227423645).

661873777795 is a wasteful number, since it uses less digits than its factorization.

661873777795 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93816374.

The product of its digits is 653456160, while the sum is 73.

The spelling of 661873777795 in words is "six hundred sixty-one billion, eight hundred seventy-three million, seven hundred seventy-seven thousand, seven hundred ninety-five".