400631945 has 32 divisors (see below), whose sum is σ = 585792000. Its totient is φ = 256766976.

The previous prime is 400631899. The next prime is 400631947. The reversal of 400631945 is 549136004.

It is a cyclic number.

It is not a de Polignac number, because 400631945 - 2⁸ = 400631689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (400631947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 86396 + ... + 90914.

It is an arithmetic number, because the mean of its divisors is an integer number (18306000).

Almost surely, 2^400631945 is an apocalyptic number.

It is an amenable number.

400631945 is a deficient number, since it is larger than the sum of its proper divisors (185160055).

400631945 is a wasteful number, since it uses less digits than its factorization.

400631945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4697.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 400631945 is about 20015.7923900104. The cubic root of 400631945 is about 737.1941131167.

Adding to 400631945 its reverse (549136004), we get a palindrome (949767949).

The spelling of 400631945 in words is "four hundred million, six hundred thirty-one thousand, nine hundred forty-five".