668720610 has 160 divisors (see below), whose sum is σ = 1886026032. Its totient is φ = 169827840.

The previous prime is 668720603. The next prime is 668720621. The reversal of 668720610 is 16027866.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 276324129 + 392396481 = 16623^2 + 19809^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1588200 + ... + 1588620.

Almost surely, 2^668720610 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668720610, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (943013016).

668720610 is an abundant number, since it is smaller than the sum of its proper divisors (1217305422).

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

668720610 is a wasteful number, since it uses less digits than its factorization.

668720610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530 (or 521 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 668720610 is about 25859.6328280198. The cubic root of 668720610 is about 874.4766873561.

The spelling of 668720610 in words is "six hundred sixty-eight million, seven hundred twenty thousand, six hundred ten".