661758872 has 32 divisors (see below), whose sum is σ = 1270080000. Its totient is φ = 323103264.

The previous prime is 661758871. The next prime is 661758893. The reversal of 661758872 is 278857166.

661758872 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 661758872.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661758871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 187379 + ... + 190877.

It is an arithmetic number, because the mean of its divisors is an integer number (39690000).

Almost surely, 2^661758872 is an apocalyptic number.

It is an amenable number.

661758872 is a deficient number, since it is larger than the sum of its proper divisors (608321128).

661758872 is a wasteful number, since it uses less digits than its factorization.

661758872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4055 (or 4051 counting only the distinct ones).

The product of its digits is 1128960, while the sum is 50.

The square root of 661758872 is about 25724.6743808352. The cubic root of 661758872 is about 871.4315059806.

The spelling of 661758872 in words is "six hundred sixty-one million, seven hundred fifty-eight thousand, eight hundred seventy-two".