400304640 has 160 divisors (see below), whose sum is σ = 1308130560. Its totient is φ = 104382464.

The previous prime is 400304633. The next prime is 400304651. The reversal of 400304640 is 46403004.

It is a tau number, because it is divible by the number of its divisors (160).

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, 360406 + ... + 361514.

It is an arithmetic number, because the mean of its divisors is an integer number (8175816).

Almost surely, 2^400304640 is an apocalyptic number.

400304640 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 400304640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (654065280).

400304640 is an abundant number, since it is smaller than the sum of its proper divisors (907825920).

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

400304640 is a wasteful number, since it uses less digits than its factorization.

400304640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1182 (or 1166 counting only the distinct ones).

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

The square root of 400304640 is about 20007.6145504655. The cubic root of 400304640 is about 736.9933028215.

Adding to 400304640 its reverse (46403004), we get a palindrome (446707644).

The spelling of 400304640 in words is "four hundred million, three hundred four thousand, six hundred forty".