664540800 has 768 divisors, whose sum is σ = 2914099200. Its totient is φ = 129024000.

The previous prime is 664540781. The next prime is 664540813. The reversal of 664540800 is 8045466.

It is a happy number.

It is a super-2 number, since 2×664540800² = 883228949729280000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 21436785 + ... + 21436815.

It is an arithmetic number, because the mean of its divisors is an integer number (3794400).

Almost surely, 2^664540800 is an apocalyptic number.

664540800 is a gapful number since it is divisible by the number (60) 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 664540800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1457049600).

664540800 is an abundant number, since it is smaller than the sum of its proper divisors (2249558400).

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

664540800 is a wasteful number, since it uses less digits than its factorization.

664540800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 664540800 is about 25778.6888727879. The cubic root of 664540800 is about 872.6509181937.

The spelling of 664540800 in words is "six hundred sixty-four million, five hundred forty thousand, eight hundred".