400406004 has 30 divisors (see below), whose sum is σ = 1046741234. Its totient is φ = 133468560.

The previous prime is 400405997. The next prime is 400406029. The reversal of 400406004 is 400604004.

It can be written as a sum of positive squares in only one way, i.e., 399200400 + 1205604 = 19980^2 + 1098^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 617587 + ... + 618234.

Almost surely, 2^400406004 is an apocalyptic number.

It is an amenable number.

400406004 is an abundant number, since it is smaller than the sum of its proper divisors (646335230).

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

400406004 is a wasteful number, since it uses less digits than its factorization.

400406004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1235837 (or 1235826 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 400406004 is about 20010.1475256931. The cubic root of 400406004 is about 737.0555040196.

The spelling of 400406004 in words is "four hundred million, four hundred six thousand, four".