400400121 has 16 divisors (see below), whose sum is σ = 582810048. Its totient is φ = 242496000.

The previous prime is 400400113. The next prime is 400400131. The reversal of 400400121 is 121004004.

It is not a de Polignac number, because 400400121 - 2³ = 400400113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 400400097 and 400400106.

It is not an unprimeable number, because it can be changed into a prime (400400131) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56065 + ... + 62801.

It is an arithmetic number, because the mean of its divisors is an integer number (36425628).

Almost surely, 2^400400121 is an apocalyptic number.

It is an amenable number.

400400121 is a deficient number, since it is larger than the sum of its proper divisors (182409927).

400400121 is a wasteful number, since it uses less digits than its factorization.

400400121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8552.

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 400400121 is about 20010.0005247376. Note that the first 3 decimals coincide. The cubic root of 400400121 is about 737.0518942512.

Adding to 400400121 its reverse (121004004), we get a palindrome (521404125).

The spelling of 400400121 in words is "four hundred million, four hundred thousand, one hundred twenty-one".