661963968 has 56 divisors (see below), whose sum is σ = 1946056560. Its totient is φ = 220654080.

The previous prime is 661963957. The next prime is 661963993. The reversal of 661963968 is 869369166.

661963968 is a `hidden beast` number, since 66 + 196 + 396 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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 7 ways as a sum of consecutive naturals, for example, 189813 + ... + 193268.

It is an arithmetic number, because the mean of its divisors is an integer number (34751010).

Almost surely, 2^661963968 is an apocalyptic number.

It is an amenable number.

661963968 is an abundant number, since it is smaller than the sum of its proper divisors (1284092592).

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

661963968 is a wasteful number, since it uses less digits than its factorization.

661963968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383102 (or 383086 counting only the distinct ones).

The product of its digits is 2519424, while the sum is 54.

The square root of 661963968 is about 25728.6604392844. The cubic root of 661963968 is about 871.5215229857.

The spelling of 661963968 in words is "six hundred sixty-one million, nine hundred sixty-three thousand, nine hundred sixty-eight".