400331813 has 24 divisors (see below), whose sum is σ = 489940992. Its totient is φ = 325521504.

The previous prime is 400331809. The next prime is 400331903. The reversal of 400331813 is 318133004.

It is a happy number.

It is not a de Polignac number, because 400331813 - 2² = 400331809 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400331803) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 141731 + ... + 144527.

It is an arithmetic number, because the mean of its divisors is an integer number (20414208).

Almost surely, 2^400331813 is an apocalyptic number.

It is an amenable number.

400331813 is a deficient number, since it is larger than the sum of its proper divisors (89609179).

400331813 is a wasteful number, since it uses less digits than its factorization.

400331813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2961 (or 2954 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 400331813 is about 20008.2936054027. The cubic root of 400331813 is about 737.0099783431.

Adding to 400331813 its reverse (318133004), we get a palindrome (718464817).

The spelling of 400331813 in words is "four hundred million, three hundred thirty-one thousand, eight hundred thirteen".