400381398640 has 20 divisors (see below), whose sum is σ = 930886752024. Its totient is φ = 160152559424.

The previous prime is 400381398617. The next prime is 400381398649. The reversal of 400381398640 is 46893183004.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400381398649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2502383662 + ... + 2502383821.

Almost surely, 2^400381398640 is an apocalyptic number.

400381398640 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

400381398640 is an abundant number, since it is smaller than the sum of its proper divisors (530505353384).

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

400381398640 is a wasteful number, since it uses less digits than its factorization.

400381398640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5004767496 (or 5004767490 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 46.

The spelling of 400381398640 in words is "four hundred billion, three hundred eighty-one million, three hundred ninety-eight thousand, six hundred forty".