399068721 has 8 divisors (see below), whose sum is σ = 591212960. Its totient is φ = 266045796.

The previous prime is 399068707. The next prime is 399068749. The reversal of 399068721 is 127860993.

It is not a de Polignac number, because 399068721 - 2¹⁴ = 399052337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399068701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7390135 + ... + 7390188.

It is an arithmetic number, because the mean of its divisors is an integer number (73901620).

Almost surely, 2^399068721 is an apocalyptic number.

It is an amenable number.

399068721 is a deficient number, since it is larger than the sum of its proper divisors (192144239).

399068721 is a wasteful number, since it uses less digits than its factorization.

399068721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14780332 (or 14780326 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The square root of 399068721 is about 19976.7044579430. The cubic root of 399068721 is about 736.2340451958.

The spelling of 399068721 in words is "three hundred ninety-nine million, sixty-eight thousand, seven hundred twenty-one".