400343640 has 64 divisors (see below), whose sum is σ = 1207388160. Its totient is φ = 106193280.

The previous prime is 400343621. The next prime is 400343651. The reversal of 400343640 is 46343004.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 400343640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14187 + ... + 31653.

It is an arithmetic number, because the mean of its divisors is an integer number (18865440).

Almost surely, 2^400343640 is an apocalyptic number.

400343640 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 400343640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (603694080).

400343640 is an abundant number, since it is smaller than the sum of its proper divisors (807044520).

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

400343640 is a wasteful number, since it uses less digits than its factorization.

400343640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17672 (or 17668 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 24.

The square root of 400343640 is about 20008.5891556601. The cubic root of 400343640 is about 737.0172360985.

Adding to 400343640 its reverse (46343004), we get a palindrome (446686644).

The spelling of 400343640 in words is "four hundred million, three hundred forty-three thousand, six hundred forty".