1231631 has 2 divisors, whose sum is σ = 1231632. Its totient is φ = 1231630.

The previous prime is 1231613. The next prime is 1231663. The reversal of 1231631 is 1361321.

Together with previous prime (1231613) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1231631 is a prime.

It is a super-2 number, since 2×1231631² = 3033829840322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615815 + 615816.

It is an arithmetic number, because the mean of its divisors is an integer number (615816).

2^1231631 is an apocalyptic number.

1231631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231631 is an equidigital number, since it uses as much as digits as its factorization.

1231631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108, while the sum is 17.

The square root of 1231631 is about 1109.7887186307. The cubic root of 1231631 is about 107.1914643367.

Adding to 1231631 its reverse (1361321), we get a palindrome (2592952).

The spelling of 1231631 in words is "one million, two hundred thirty-one thousand, six hundred thirty-one".