390921280 has 112 divisors (see below), whose sum is σ = 967014576. Its totient is φ = 150405120.

The previous prime is 390921259. The next prime is 390921283. The reversal of 390921280 is 82129093.

It can be written as a sum of positive squares in 8 ways, for example, as 41679936 + 349241344 = 6456^2 + 18688^2 .

It is not an unprimeable number, because it can be changed into a prime (390921283) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1621960 + ... + 1622200.

Almost surely, 2^390921280 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 390921280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (483507288).

390921280 is an abundant number, since it is smaller than the sum of its proper divisors (576093296).

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

390921280 is a wasteful number, since it uses less digits than its factorization.

390921280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432 (or 422 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 390921280 is about 19771.7293123288. The cubic root of 390921280 is about 731.1892044813.

The spelling of 390921280 in words is "three hundred ninety million, nine hundred twenty-one thousand, two hundred eighty".