668820020 has 24 divisors (see below), whose sum is σ = 1532206368. Its totient is φ = 243207200.

The previous prime is 668819999. The next prime is 668820023. The reversal of 668820020 is 20028866.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668820023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1519826 + ... + 1520265.

It is an arithmetic number, because the mean of its divisors is an integer number (63841932).

Almost surely, 2^668820020 is an apocalyptic number.

It is an amenable number.

668820020 is an abundant number, since it is smaller than the sum of its proper divisors (863386348).

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

668820020 is a wasteful number, since it uses less digits than its factorization.

668820020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3040111 (or 3040109 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 668820020 is about 25861.5548643155. The cubic root of 668820020 is about 874.5200175695.

Adding to 668820020 its reverse (20028866), we get a palindrome (688848886).

The spelling of 668820020 in words is "six hundred sixty-eight million, eight hundred twenty thousand, twenty".