668199820 has 12 divisors (see below), whose sum is σ = 1403219664. Its totient is φ = 267279920.

The previous prime is 668199811. The next prime is 668199821. The reversal of 668199820 is 28991866.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (668199821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16704976 + ... + 16705015.

It is an arithmetic number, because the mean of its divisors is an integer number (116934972).

Almost surely, 2^668199820 is an apocalyptic number.

It is an amenable number.

668199820 is an abundant number, since it is smaller than the sum of its proper divisors (735019844).

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

668199820 is a wasteful number, since it uses less digits than its factorization.

668199820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33410000 (or 33409998 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 49.

The square root of 668199820 is about 25849.5613115581. The cubic root of 668199820 is about 874.2496184413.

The spelling of 668199820 in words is "six hundred sixty-eight million, one hundred ninety-nine thousand, eight hundred twenty".