400644660 has 96 divisors (see below), whose sum is σ = 1213914240. Its totient is φ = 98145792.

The previous prime is 400644641. The next prime is 400644667. The reversal of 400644660 is 66446004.

It is a super-2 number, since 2×400644660² = 321032287173031200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400644667) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 177499 + ... + 179741.

It is an arithmetic number, because the mean of its divisors is an integer number (12644940).

Almost surely, 2^400644660 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 400644660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (606957120).

400644660 is an abundant number, since it is smaller than the sum of its proper divisors (813269580).

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

400644660 is a wasteful number, since it uses less digits than its factorization.

400644660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2497 (or 2495 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 400644660 is about 20016.1100116881. The cubic root of 400644660 is about 737.2019118990.

The spelling of 400644660 in words is "four hundred million, six hundred forty-four thousand, six hundred sixty".