664431240 has 128 divisors (see below), whose sum is σ = 2227720320. Its totient is φ = 157132800.

The previous prime is 664431223. The next prime is 664431289. The reversal of 664431240 is 42134466.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 664431198 and 664431207.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 47982 + ... + 60258.

It is an arithmetic number, because the mean of its divisors is an integer number (17404065).

Almost surely, 2^664431240 is an apocalyptic number.

664431240 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 664431240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1113860160).

664431240 is an abundant number, since it is smaller than the sum of its proper divisors (1563289080).

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

664431240 is a wasteful number, since it uses less digits than its factorization.

664431240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12343 (or 12339 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 664431240 is about 25776.5637740953. The cubic root of 664431240 is about 872.6029588162.

The spelling of 664431240 in words is "six hundred sixty-four million, four hundred thirty-one thousand, two hundred forty".