399921290 has 8 divisors (see below), whose sum is σ = 719858340. Its totient is φ = 159968512.

The previous prime is 399921289. The next prime is 399921341. The reversal of 399921290 is 92129993.

It can be written as a sum of positive squares in 2 ways, for example, as 367987489 + 31933801 = 19183^2 + 5651^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19996055 + ... + 19996074.

Almost surely, 2^399921290 is an apocalyptic number.

399921290 is a deficient number, since it is larger than the sum of its proper divisors (319937050).

399921290 is a wasteful number, since it uses less digits than its factorization.

399921290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39992136.

The product of its (nonzero) digits is 78732, while the sum is 44.

The square root of 399921290 is about 19998.0321531895. The cubic root of 399921290 is about 736.7579682046.

The spelling of 399921290 in words is "three hundred ninety-nine million, nine hundred twenty-one thousand, two hundred ninety".