665821119658464 has 1344 divisors, whose sum is σ = 2531493371215872. Its totient is φ = 167220273484800.

The previous prime is 665821119658441. The next prime is 665821119658511. The reversal of 665821119658464 is 464856911128566.

665821119658464 is a `hidden beast` number, since 6 + 6 + 5 + 8 + 21 + 1 + 1 + 96 + 58 + 464 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 665821119658392 and 665821119658401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 76119936139 + ... + 76119944885.

It is an arithmetic number, because the mean of its divisors is an integer number (1883551615488).

Almost surely, 2^{665821119658464} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665821119658464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1265746685607936).

665821119658464 is an abundant number, since it is smaller than the sum of its proper divisors (1865672251557408).

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

665821119658464 is a wasteful number, since it uses less digits than its factorization.

665821119658464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10191 (or 10168 counting only the distinct ones).

The product of its digits is 597196800, while the sum is 72.

The spelling of 665821119658464 in words is "six hundred sixty-five trillion, eight hundred twenty-one billion, one hundred nineteen million, six hundred fifty-eight thousand, four hundred sixty-four".