661266864 has 30 divisors (see below), whose sum is σ = 1850629196. Its totient is φ = 220422240.

The previous prime is 661266821. The next prime is 661266877. The reversal of 661266864 is 468662166.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2295922 + ... + 2296209.

Almost surely, 2^661266864 is an apocalyptic number.

It is an amenable number.

661266864 is an abundant number, since it is smaller than the sum of its proper divisors (1189362332).

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

661266864 is a wasteful number, since it uses less digits than its factorization.

661266864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4592145 (or 4592136 counting only the distinct ones).

The product of its digits is 497664, while the sum is 45.

The square root of 661266864 is about 25715.1096439428. The cubic root of 661266864 is about 871.2154869283.

The spelling of 661266864 in words is "six hundred sixty-one million, two hundred sixty-six thousand, eight hundred sixty-four".