400403640 has 256 divisors, whose sum is σ = 1519902720. Its totient is φ = 82114560.

The previous prime is 400403611. The next prime is 400403683. The reversal of 400403640 is 46304004.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 403545 + ... + 404535.

It is an arithmetic number, because the mean of its divisors is an integer number (5937120).

Almost surely, 2^400403640 is an apocalyptic number.

400403640 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 400403640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (759951360).

400403640 is an abundant number, since it is smaller than the sum of its proper divisors (1119499080).

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

400403640 is a wasteful number, since it uses less digits than its factorization.

400403640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1062 (or 1058 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 400403640 is about 20010.0884555766. The cubic root of 400403640 is about 737.0540534897.

Adding to 400403640 its reverse (46304004), we get a palindrome (446707644).

The spelling of 400403640 in words is "four hundred million, four hundred three thousand, six hundred forty".