668788428 has 48 divisors (see below), whose sum is σ = 1945569024. Its totient is φ = 173711040.

The previous prime is 668788409. The next prime is 668788447. The reversal of 668788428 is 824887866.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (668788409) and next prime (668788447).

It is a super-2 number, since 2×668788428² = 894555922853422368, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 360975 + ... + 362822.

It is an arithmetic number, because the mean of its divisors is an integer number (40532688).

Almost surely, 2^668788428 is an apocalyptic number.

It is an amenable number.

668788428 is an abundant number, since it is smaller than the sum of its proper divisors (1276780596).

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

668788428 is a wasteful number, since it uses less digits than its factorization.

668788428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 723822 (or 723820 counting only the distinct ones).

The product of its digits is 8257536, while the sum is 57.

The square root of 668788428 is about 25860.9440662943. The cubic root of 668788428 is about 874.5062479102.

The spelling of 668788428 in words is "six hundred sixty-eight million, seven hundred eighty-eight thousand, four hundred twenty-eight".