400400125 has 16 divisors (see below), whose sum is σ = 513210672. Its totient is φ = 311659200.

The previous prime is 400400113. The next prime is 400400131. The reversal of 400400125 is 521004004.

It can be written as a sum of positive squares in 8 ways, for example, as 132848676 + 267551449 = 11526^2 + 16357^2 .

It is not a de Polignac number, because 400400125 - 2¹⁷ = 400269053 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400400099 and 400400108.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38662 + ... + 47911.

It is an arithmetic number, because the mean of its divisors is an integer number (32075667).

Almost surely, 2^400400125 is an apocalyptic number.

It is an amenable number.

400400125 is a deficient number, since it is larger than the sum of its proper divisors (112810547).

400400125 is an equidigital number, since it uses as much as digits as its factorization.

400400125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86625 (or 86615 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 400400125 is about 20010.0006246876. Note that the first 3 decimals coincide. The cubic root of 400400125 is about 737.0518967056.

Adding to 400400125 its reverse (521004004), we get a palindrome (921404129).

It can be divided in two parts, 4004001 and 25, that multiplied together give a square (100100025 = 10005²).

The spelling of 400400125 in words is "four hundred million, four hundred thousand, one hundred twenty-five".