399920020 has 12 divisors (see below), whose sum is σ = 839832084. Its totient is φ = 159968000.

The previous prime is 399920009. The next prime is 399920029. The reversal of 399920020 is 20029993.

It can be written as a sum of positive squares in 2 ways, for example, as 144048004 + 255872016 = 12002^2 + 15996^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399920029) 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, 9997981 + ... + 9998020.

It is an arithmetic number, because the mean of its divisors is an integer number (69986007).

Almost surely, 2^399920020 is an apocalyptic number.

It is an amenable number.

399920020 is an abundant number, since it is smaller than the sum of its proper divisors (439912064).

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

399920020 is a wasteful number, since it uses less digits than its factorization.

399920020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19996010 (or 19996008 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 34.

The square root of 399920020 is about 19998.0004000400. Note that the first 3 decimals coincide. The cubic root of 399920020 is about 736.7571883148.

The spelling of 399920020 in words is "three hundred ninety-nine million, nine hundred twenty thousand, twenty".