668915520 has 672 divisors, whose sum is σ = 2855854080. Its totient is φ = 129392640.

The previous prime is 668915519. The next prime is 668915521. The reversal of 668915520 is 25519866.

It is an interprime number because it is at equal distance from previous prime (668915519) and next prime (668915521).

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668915521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 21577905 + ... + 21577935.

Almost surely, 2^668915520 is an apocalyptic number.

668915520 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 668915520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1427927040).

668915520 is an abundant number, since it is smaller than the sum of its proper divisors (2186938560).

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

668915520 is a wasteful number, since it uses less digits than its factorization.

668915520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103 (or 80 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 42.

The square root of 668915520 is about 25863.4011684465. The cubic root of 668915520 is about 874.5616394729.

The spelling of 668915520 in words is "six hundred sixty-eight million, nine hundred fifteen thousand, five hundred twenty".