399807720 has 96 divisors (see below), whose sum is σ = 1399343400. Its totient is φ = 98413056.

The previous prime is 399807613. The next prime is 399807721. The reversal of 399807720 is 27708993.

It can be written as a sum of positive squares in 4 ways, for example, as 112911876 + 286895844 = 10626^2 + 16938^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (399807721) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38035 + ... + 47394.

Almost surely, 2^399807720 is an apocalyptic number.

399807720 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

399807720 is an abundant number, since it is smaller than the sum of its proper divisors (999535680).

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

399807720 is a wasteful number, since it uses less digits than its factorization.

399807720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85459 (or 85452 counting only the distinct ones).

The product of its (nonzero) digits is 190512, while the sum is 45.

The square root of 399807720 is about 19995.1924221799. The cubic root of 399807720 is about 736.6882198763.

The spelling of 399807720 in words is "three hundred ninety-nine million, eight hundred seven thousand, seven hundred twenty".