2399125285921 has 27 divisors (see below), whose sum is σ = 3022188890553. Its totient is φ = 1898097495840.

The previous prime is 2399125285811. The next prime is 2399125285933. The reversal of 2399125285921 is 1295825219932.

The square root of 2399125285921 is 1548911.

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

It can be written as a sum of positive squares in 4 ways, for example, as 120426350625 + 2278698935296 = 347025^2 + 1509536^2 .

It is not a de Polignac number, because 2399125285921 - 2¹⁵ = 2399125253153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2399125288921) 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 26 ways as a sum of consecutive naturals, for example, 140942391 + ... + 140959411.

Almost surely, 2^{2399125285921} is an apocalyptic number.

2399125285921 is the 1548911-st square number.

2399125285921 is the 774456-th centered octagonal number.

It is an amenable number.

2399125285921 is a deficient number, since it is larger than the sum of its proper divisors (623063604632).

2399125285921 is an frugal number, since it uses more digits than its factorization.

2399125285921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34082 (or 17041 counting only the distinct ones).

The product of its digits is 6998400, while the sum is 58.

The spelling of 2399125285921 in words is "two trillion, three hundred ninety-nine billion, one hundred twenty-five million, two hundred eighty-five thousand, nine hundred twenty-one".