399695806225 has 9 divisors (see below), whose sum is σ = 495626719483. Its totient is φ = 319754116120.

The previous prime is 399695806217. The next prime is 399695806229. The reversal of 399695806225 is 522608596993.

It is a happy number.

The square root of 399695806225 is 632215.

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

It can be written as a sum of positive squares in only one way, i.e., 143890490241 + 255805315984 = 379329^2 + 505772^2 .

It is not a de Polignac number, because 399695806225 - 2³ = 399695806217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399695806229) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3097854 + ... + 3224296.

Almost surely, 2^399695806225 is an apocalyptic number.

399695806225 is the 632215-th square number.

399695806225 is the 316108-th centered octagonal number.

It is an amenable number.

399695806225 is a deficient number, since it is larger than the sum of its proper divisors (95930913258).

399695806225 is an frugal number, since it uses more digits than its factorization.

399695806225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252896 (or 126448 counting only the distinct ones).

The product of its (nonzero) digits is 62985600, while the sum is 64.

Multiplying 399695806225 by its sum of digits (64), we get a square (25580531598400 = 5057720²).

The spelling of 399695806225 in words is "three hundred ninety-nine billion, six hundred ninety-five million, eight hundred six thousand, two hundred twenty-five".