399071221 has 16 divisors (see below), whose sum is σ = 413683200. Its totient is φ = 384798448.

The previous prime is 399071213. The next prime is 399071237. The reversal of 399071221 is 122170993.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 399071221 - 2³ = 399071213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399071521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1111440 + ... + 1111798.

It is an arithmetic number, because the mean of its divisors is an integer number (25855200).

Almost surely, 2^399071221 is an apocalyptic number.

It is an amenable number.

399071221 is a deficient number, since it is larger than the sum of its proper divisors (14611979).

399071221 is a wasteful number, since it uses less digits than its factorization.

399071221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 728.

The product of its (nonzero) digits is 6804, while the sum is 34.

The square root of 399071221 is about 19976.7670307285. The cubic root of 399071221 is about 736.2355825929.

The spelling of 399071221 in words is "three hundred ninety-nine million, seventy-one thousand, two hundred twenty-one".