400404042 has 24 divisors (see below), whose sum is σ = 868857444. Its totient is φ = 133265664.

The previous prime is 400404019. The next prime is 400404049. The reversal of 400404042 is 240404004.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 396447921 + 3956121 = 19911^2 + 1989^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (400404049) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4413 + ... + 28640.

Almost surely, 2^400404042 is an apocalyptic number.

400404042 is an abundant number, since it is smaller than the sum of its proper divisors (468453402).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

400404042 is a wasteful number, since it uses less digits than its factorization.

400404042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33734 (or 33731 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 18.

The square root of 400404042 is about 20010.0985005072. The cubic root of 400404042 is about 737.0543001538.

Adding to 400404042 its reverse (240404004), we get a palindrome (640808046).

The spelling of 400404042 in words is "four hundred million, four hundred four thousand, forty-two".