400609638 has 80 divisors (see below), whose sum is σ = 1054657296. Its totient is φ = 112052160.

The previous prime is 400609637. The next prime is 400609663. The reversal of 400609638 is 836906004.

400609638 is a `hidden beast` number, since 40 + 0 + 609 + 6 + 3 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400609633) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 14520 + ... + 31812.

Almost surely, 2^400609638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400609638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (527328648).

400609638 is an abundant number, since it is smaller than the sum of its proper divisors (654047658).

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

400609638 is a wasteful number, since it uses less digits than its factorization.

400609638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17331 (or 17322 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 400609638 is about 20015.2351472572. The cubic root of 400609638 is about 737.1804306545.

The spelling of 400609638 in words is "four hundred million, six hundred nine thousand, six hundred thirty-eight".