400405187440 has 80 divisors (see below), whose sum is σ = 986644752480. Its totient is φ = 150596812800.

The previous prime is 400405187419. The next prime is 400405187597. The reversal of 400405187440 is 44781504004.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a self number, because there is not a number n which added to its sum of digits gives 400405187440.

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 15 ways as a sum of consecutive naturals, for example, 1289296 + ... + 1569424.

It is an arithmetic number, because the mean of its divisors is an integer number (12333059406).

Almost surely, 2^400405187440 is an apocalyptic number.

400405187440 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 400405187440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (493322376240).

400405187440 is an abundant number, since it is smaller than the sum of its proper divisors (586239565040).

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

400405187440 is a wasteful number, since it uses less digits than its factorization.

400405187440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281210 (or 281204 counting only the distinct ones).

The product of its (nonzero) digits is 71680, while the sum is 37.

The spelling of 400405187440 in words is "four hundred billion, four hundred five million, one hundred eighty-seven thousand, four hundred forty".