400081644 has 18 divisors (see below), whose sum is σ = 1011317580. Its totient is φ = 133360536.

The previous prime is 400081639. The next prime is 400081679. The reversal of 400081644 is 446180004.

It is a tau number, because it is divible by the number of its divisors (18).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5556654 + ... + 5556725.

It is an arithmetic number, because the mean of its divisors is an integer number (56184310).

Almost surely, 2^400081644 is an apocalyptic number.

It is an amenable number.

400081644 is an abundant number, since it is smaller than the sum of its proper divisors (611235936).

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

400081644 is a wasteful number, since it uses less digits than its factorization.

400081644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11113389 (or 11113384 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 400081644 is about 20002.0409958584. The cubic root of 400081644 is about 736.8564261624.

The spelling of 400081644 in words is "four hundred million, eighty-one thousand, six hundred forty-four".