664187500 has 42 divisors (see below), whose sum is σ = 1453028276. Its totient is φ = 265650000.

The previous prime is 664187479. The next prime is 664187519. The reversal of 664187500 is 5781466.

It is a super-2 number, since 2×664187500² = 882290070312500000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 664187500.

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 57187 + ... + 67813.

Almost surely, 2^664187500 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 664187500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (726514138).

664187500 is an abundant number, since it is smaller than the sum of its proper divisors (788840776).

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

664187500 is an equidigital number, since it uses as much as digits as its factorization.

664187500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10661 (or 10634 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 664187500 is about 25771.8354022371. The cubic root of 664187500 is about 872.4962438570.

The spelling of 664187500 in words is "six hundred sixty-four million, one hundred eighty-seven thousand, five hundred".