400405783680 has 640 divisors, whose sum is σ = 1657319304960. Its totient is φ = 90226483200.

The previous prime is 400405783649. The next prime is 400405783699. The reversal of 400405783680 is 86387504004.

400405783680 is a `hidden beast` number, since 4 + 0 + 0 + 40 + 578 + 36 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 25756710 + ... + 25772250.

It is an arithmetic number, because the mean of its divisors is an integer number (2589561414).

Almost surely, 2^400405783680 is an apocalyptic number.

400405783680 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 400405783680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (828659652480).

400405783680 is an abundant number, since it is smaller than the sum of its proper divisors (1256913521280).

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

400405783680 is a wasteful number, since it uses less digits than its factorization.

400405783680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15650 (or 15629 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 45.

The spelling of 400405783680 in words is "four hundred billion, four hundred five million, seven hundred eighty-three thousand, six hundred eighty".