661751772 has 48 divisors (see below), whose sum is σ = 1700237952. Its totient is φ = 198652480.

The previous prime is 661751759. The next prime is 661751777. The reversal of 661751772 is 277157166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661751777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9303 + ... + 37550.

It is an arithmetic number, because the mean of its divisors is an integer number (35421624).

Almost surely, 2^661751772 is an apocalyptic number.

It is an amenable number.

661751772 is an abundant number, since it is smaller than the sum of its proper divisors (1038486180).

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

661751772 is a wasteful number, since it uses less digits than its factorization.

661751772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46978 (or 46976 counting only the distinct ones).

The product of its digits is 123480, while the sum is 42.

The square root of 661751772 is about 25724.5363806619. The cubic root of 661751772 is about 871.4283894447.

The spelling of 661751772 in words is "six hundred sixty-one million, seven hundred fifty-one thousand, seven hundred seventy-two".