400020631 has 2 divisors, whose sum is σ = 400020632. Its totient is φ = 400020630.

The previous prime is 400020613. The next prime is 400020637. The reversal of 400020631 is 136020004.

Together with previous prime (400020613) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 400020631 - 2¹⁷ = 399889559 is a prime.

It is a super-2 number, since 2×400020631² = 320033010451276322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400020637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200010315 + 200010316.

It is an arithmetic number, because the mean of its divisors is an integer number (200010316).

Almost surely, 2^400020631 is an apocalyptic number.

400020631 is a deficient number, since it is larger than the sum of its proper divisors (1).

400020631 is an equidigital number, since it uses as much as digits as its factorization.

400020631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 400020631 is about 20000.5157683496. The cubic root of 400020631 is about 736.8189670526.

Adding to 400020631 its reverse (136020004), we get a palindrome (536040635).

The spelling of 400020631 in words is "four hundred million, twenty thousand, six hundred thirty-one".