668720880 has 160 divisors (see below), whose sum is σ = 2335475520. Its totient is φ = 175841280.

The previous prime is 668720879. The next prime is 668720881. The reversal of 668720880 is 88027866.

It is an interprime number because it is at equal distance from previous prime (668720879) and next prime (668720881).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668720881) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 155560 + ... + 159800.

It is an arithmetic number, because the mean of its divisors is an integer number (14596722).

Almost surely, 2^668720880 is an apocalyptic number.

668720880 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 668720880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1167737760).

668720880 is an abundant number, since it is smaller than the sum of its proper divisors (1666754640).

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

668720880 is a wasteful number, since it uses less digits than its factorization.

668720880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4336 (or 4324 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The square root of 668720880 is about 25859.6380485110. The cubic root of 668720880 is about 874.4768050478.

The spelling of 668720880 in words is "six hundred sixty-eight million, seven hundred twenty thousand, eight hundred eighty".