400188631 has 2 divisors, whose sum is σ = 400188632. Its totient is φ = 400188630.

The previous prime is 400188623. The next prime is 400188643. The reversal of 400188631 is 136881004.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 400188631 - 2³ = 400188623 is a prime.

It is a super-2 number, since 2×400188631² = 320301880763308322, which contains 22 as substring.

It is equal to p_21345817 and since 400188631 and 21345817 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 400188593 and 400188602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400188601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200094315 + 200094316.

It is an arithmetic number, because the mean of its divisors is an integer number (200094316).

Almost surely, 2^400188631 is an apocalyptic number.

400188631 is a deficient number, since it is larger than the sum of its proper divisors (1).

400188631 is an equidigital number, since it uses as much as digits as its factorization.

400188631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 400188631 is about 20004.7152191677. The cubic root of 400188631 is about 736.9221019510.

The spelling of 400188631 in words is "four hundred million, one hundred eighty-eight thousand, six hundred thirty-one".