400644518400 has 1440 divisors, whose sum is σ = 1751978342400. Its totient is φ = 85399142400.

The previous prime is 400644518357. The next prime is 400644518429. The reversal of 400644518400 is 4815446004.

It is a happy number.

400644518400 is a `hidden beast` number, since 4 + 0 + 0 + 644 + 5 + 1 + 8 + 4 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 1210406235 + ... + 1210406565.

Almost surely, 2^400644518400 is an apocalyptic number.

400644518400 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400644518400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (875989171200).

400644518400 is an abundant number, since it is smaller than the sum of its proper divisors (1351333824000).

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

400644518400 is a wasteful number, since it uses less digits than its factorization.

400644518400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470 (or 446 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 36.

The spelling of 400644518400 in words is "four hundred billion, six hundred forty-four million, five hundred eighteen thousand, four hundred".