664599780 has 144 divisors (see below), whose sum is σ = 2183860224. Its totient is φ = 162627840.

The previous prime is 664599779. The next prime is 664599799. The reversal of 664599780 is 87995466.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 446197 + ... + 447683.

It is an arithmetic number, because the mean of its divisors is an integer number (15165696).

Almost surely, 2^664599780 is an apocalyptic number.

664599780 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 664599780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1091930112).

664599780 is an abundant number, since it is smaller than the sum of its proper divisors (1519260444).

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

664599780 is a wasteful number, since it uses less digits than its factorization.

664599780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706 (or 1701 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 54.

The square root of 664599780 is about 25779.8328155944. The cubic root of 664599780 is about 872.6767342302.

The spelling of 664599780 in words is "six hundred sixty-four million, five hundred ninety-nine thousand, seven hundred eighty".