668400525 has 144 divisors (see below), whose sum is σ = 1402201920. Its totient is φ = 310262400.

The previous prime is 668400503. The next prime is 668400529. The reversal of 668400525 is 525004866.

It is a de Polignac number, because none of the positive numbers 2^k-668400525 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 668400525.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668400529) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 3167670 + ... + 3167880.

Almost surely, 2^668400525 is an apocalyptic number.

668400525 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

668400525 is an abundant number, since it is smaller than the sum of its proper divisors (733801395).

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

668400525 is a wasteful number, since it uses less digits than its factorization.

668400525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 668400525 is about 25853.4431942827. The cubic root of 668400525 is about 874.3371415141.

The spelling of 668400525 in words is "six hundred sixty-eight million, four hundred thousand, five hundred twenty-five".