390904820 has 18 divisors (see below), whose sum is σ = 821085846. Its totient is φ = 156326560.

The previous prime is 390904751. The next prime is 390904831. The reversal of 390904820 is 28409093.

It can be written as a sum of positive squares in 3 ways, for example, as 155650576 + 235254244 = 12476^2 + 15338^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 86210 + ... + 90630.

Almost surely, 2^390904820 is an apocalyptic number.

It is an amenable number.

390904820 is an abundant number, since it is smaller than the sum of its proper divisors (430181026).

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

390904820 is an frugal number, since it uses more digits than its factorization.

390904820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8851 (or 4428 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 390904820 is about 19771.3130570531. The cubic root of 390904820 is about 731.1789419350.

The spelling of 390904820 in words is "three hundred ninety million, nine hundred four thousand, eight hundred twenty".