399400225 has 27 divisors (see below), whose sum is σ = 577125171. Its totient is φ = 273394800.

The previous prime is 399400213. The next prime is 399400231. The reversal of 399400225 is 522004993.

The square root of 399400225 is 19985.

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., 143784081 + 255616144 = 11991^2 + 15988^2 .

It is not a de Polignac number, because 399400225 - 2⁷ = 399400097 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 699190 + ... + 699760.

Almost surely, 2^399400225 is an apocalyptic number.

399400225 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

399400225 is the 19985-th square number.

399400225 is the 9993-rd centered octagonal number.

It is an amenable number.

399400225 is a deficient number, since it is larger than the sum of its proper divisors (177724946).

399400225 is an frugal number, since it uses more digits than its factorization.

399400225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166 (or 583 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 34.

The cubic root of 399400225 is about 736.4378505125.

The spelling of 399400225 in words is "three hundred ninety-nine million, four hundred thousand, two hundred twenty-five".