661966312 has 128 divisors (see below), whose sum is σ = 1559347200. Its totient is φ = 257241600.

The previous prime is 661966259. The next prime is 661966321. The reversal of 661966312 is 213669166.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 2355612 + ... + 2355892.

It is an arithmetic number, because the mean of its divisors is an integer number (12182400).

Almost surely, 2^661966312 is an apocalyptic number.

661966312 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661966312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (779673600).

661966312 is an abundant number, since it is smaller than the sum of its proper divisors (897380888).

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

661966312 is a wasteful number, since it uses less digits than its factorization.

661966312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407 (or 403 counting only the distinct ones).

The product of its digits is 69984, while the sum is 40.

The square root of 661966312 is about 25728.7059915574. The cubic root of 661966312 is about 871.5225516641.

The spelling of 661966312 in words is "six hundred sixty-one million, nine hundred sixty-six thousand, three hundred twelve".