664145664 has 432 divisors, whose sum is σ = 2369993472. Its totient is φ = 161021952.

The previous prime is 664145663. The next prime is 664145693. The reversal of 664145664 is 466541466.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664145663) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 15445227 + ... + 15445269.

It is an arithmetic number, because the mean of its divisors is an integer number (5486096).

Almost surely, 2^664145664 is an apocalyptic number.

664145664 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 664145664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1184996736).

664145664 is an abundant number, since it is smaller than the sum of its proper divisors (1705847808).

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

664145664 is a wasteful number, since it uses less digits than its factorization.

664145664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112 (or 85 counting only the distinct ones).

The product of its digits is 414720, while the sum is 42.

The square root of 664145664 is about 25771.0237282107. The cubic root of 664145664 is about 872.4779244722.

The spelling of 664145664 in words is "six hundred sixty-four million, one hundred forty-five thousand, six hundred sixty-four".