399560121 has 15 divisors (see below), whose sum is σ = 597142623. Its totient is φ = 266253480.

The previous prime is 399560111. The next prime is 399560153. The reversal of 399560121 is 121065993.

The square root of 399560121 is 19989.

It is a perfect power (a square), and thus also a powerful number.

399560121 is a `hidden beast` number, since 3 + 99 + 560 + 1 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 270964521 + 128595600 = 16461^2 + 11340^2 .

It is not a de Polignac number, because 399560121 - 2⁹ = 399559609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (399560111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 178791 + ... + 181011.

Almost surely, 2^399560121 is an apocalyptic number.

399560121 is the 19989-th square number.

399560121 is the 9995-th centered octagonal number.

It is an amenable number.

399560121 is a deficient number, since it is larger than the sum of its proper divisors (197582502).

399560121 is an frugal number, since it uses more digits than its factorization.

399560121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4454 (or 2224 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The cubic root of 399560121 is about 736.5361126472.

Multiplying 399560121 by its sum of digits (36), we get a square (14384164356 = 119934²).

The spelling of 399560121 in words is "three hundred ninety-nine million, five hundred sixty thousand, one hundred twenty-one".