400556720 has 80 divisors (see below), whose sum is σ = 989936640. Its totient is φ = 150208512.

The previous prime is 400556687. The next prime is 400556731. The reversal of 400556720 is 27655004.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 520496 + ... + 521264.

It is an arithmetic number, because the mean of its divisors is an integer number (12374208).

Almost surely, 2^400556720 is an apocalyptic number.

400556720 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 400556720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (494968320).

400556720 is an abundant number, since it is smaller than the sum of its proper divisors (589379920).

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

400556720 is a wasteful number, since it uses less digits than its factorization.

400556720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1182 (or 1176 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 29.

The square root of 400556720 is about 20013.9131605991. The cubic root of 400556720 is about 737.1479702674.

The spelling of 400556720 in words is "four hundred million, five hundred fifty-six thousand, seven hundred twenty".