665168251264 has 128 divisors (see below), whose sum is σ = 1547846042400. Its totient is φ = 281365708800.

The previous prime is 665168251243. The next prime is 665168251277. The reversal of 665168251264 is 462152861566.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1974184 + ... + 2286424.

Almost surely, 2^665168251264 is an apocalyptic number.

665168251264 is a gapful number since it is divisible by the number (64) 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 665168251264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (773923021200).

665168251264 is an abundant number, since it is smaller than the sum of its proper divisors (882677791136).

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

665168251264 is a wasteful number, since it uses less digits than its factorization.

665168251264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312372 (or 312360 counting only the distinct ones).

The product of its digits is 4147200, while the sum is 52.

The spelling of 665168251264 in words is "six hundred sixty-five billion, one hundred sixty-eight million, two hundred fifty-one thousand, two hundred sixty-four".