400003644 has 12 divisors (see below), whose sum is σ = 933341864. Its totient is φ = 133334544.

The previous prime is 400003627. The next prime is 400003651. The reversal of 400003644 is 446300004.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 400003644.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16666807 + ... + 16666830.

Almost surely, 2^400003644 is an apocalyptic number.

It is an amenable number.

400003644 is an abundant number, since it is smaller than the sum of its proper divisors (533338220).

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

400003644 is a wasteful number, since it uses less digits than its factorization.

400003644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33333644 (or 33333642 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 400003644 is about 20000.0910997925. The cubic root of 400003644 is about 736.8085371564.

Adding to 400003644 its reverse (446300004), we get a palindrome (846303648).

The spelling of 400003644 in words is "four hundred million, three thousand, six hundred forty-four".