664940520 has 96 divisors (see below), whose sum is σ = 2164406400. Its totient is φ = 177042816.

The previous prime is 664940513. The next prime is 664940527. The reversal of 664940520 is 25049466.

664940520 is a `hidden beast` number, since 6 + 649 + 4 + 0 + 5 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (664940513) and next prime (664940527).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (664940527) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 352941 + ... + 354819.

It is an arithmetic number, because the mean of its divisors is an integer number (22545900).

Almost surely, 2^664940520 is an apocalyptic number.

664940520 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 664940520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1082203200).

664940520 is an abundant number, since it is smaller than the sum of its proper divisors (1499465880).

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

664940520 is a wasteful number, since it uses less digits than its factorization.

664940520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2879 (or 2872 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 664940520 is about 25786.4406229320. The cubic root of 664940520 is about 872.8258490688.

Adding to 664940520 its reverse (25049466), we get a palindrome (689989986).

The spelling of 664940520 in words is "six hundred sixty-four million, nine hundred forty thousand, five hundred twenty".