400001121 has 24 divisors (see below), whose sum is σ = 625054976. Its totient is φ = 245034720.

The previous prime is 400001113. The next prime is 400001137. The reversal of 400001121 is 121100004.

It is a happy number.

It is not a de Polignac number, because 400001121 - 2³ = 400001113 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (400001101) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18426 + ... + 33756.

Almost surely, 2^400001121 is an apocalyptic number.

It is an amenable number.

400001121 is a deficient number, since it is larger than the sum of its proper divisors (225053855).

400001121 is a wasteful number, since it uses less digits than its factorization.

400001121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15573 (or 15570 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 400001121 is about 20000.0280249804. The cubic root of 400001121 is about 736.8069880273.

Adding to 400001121 its reverse (121100004), we get a palindrome (521101125).

The spelling of 400001121 in words is "four hundred million, one thousand, one hundred twenty-one".