664392861810 has 80 divisors (see below), whose sum is σ = 1788683162112. Its totient is φ = 176952794400.

The previous prime is 664392861791. The next prime is 664392861823. The reversal of 664392861810 is 18168293466.

664392861810 is a `hidden beast` number, since 6 + 6 + 4 + 3 + 9 + 2 + 8 + 618 + 10 = 666.

It is a super-2 number, since 2×664392861810² (a number of 24 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 151215 + ... + 1162605.

Almost surely, 2^664392861810 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664392861810, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (894341581056).

664392861810 is an abundant number, since it is smaller than the sum of its proper divisors (1124290300302).

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

664392861810 is a wasteful number, since it uses less digits than its factorization.

664392861810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1012221 (or 1012212 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The spelling of 664392861810 in words is "six hundred sixty-four billion, three hundred ninety-two million, eight hundred sixty-one thousand, eight hundred ten".