400631643 has 8 divisors (see below), whose sum is σ = 593528400. Its totient is φ = 267087744.

The previous prime is 400631633. The next prime is 400631657. The reversal of 400631643 is 346136004.

It is not a de Polignac number, because 400631643 - 2⁶ = 400631579 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 14838209 = 400631643 / (4 + 0 + 0 + 6 + 3 + 1 + 6 + 4 + 3).

It is not an unprimeable number, because it can be changed into a prime (400631633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7419078 + ... + 7419131.

It is an arithmetic number, because the mean of its divisors is an integer number (74191050).

Almost surely, 2^400631643 is an apocalyptic number.

400631643 is a deficient number, since it is larger than the sum of its proper divisors (192896757).

400631643 is a wasteful number, since it uses less digits than its factorization.

400631643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14838218 (or 14838212 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 400631643 is about 20015.7848459659. The cubic root of 400631643 is about 737.1939278821.

Adding to 400631643 its reverse (346136004), we get a palindrome (746767647).

The spelling of 400631643 in words is "four hundred million, six hundred thirty-one thousand, six hundred forty-three".