1591631 has 2 divisors, whose sum is σ = 1591632. Its totient is φ = 1591630.

The previous prime is 1591621. The next prime is 1591637. The reversal of 1591631 is 1361951.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1591631 - 2⁶ = 1591567 is a prime.

It is a super-2 number, since 2×1591631² = 5066578480322, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1591631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1591637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 795815 + 795816.

It is an arithmetic number, because the mean of its divisors is an integer number (795816).

2^1591631 is an apocalyptic number.

1591631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1591631 is an equidigital number, since it uses as much as digits as its factorization.

1591631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 810, while the sum is 26.

The square root of 1591631 is about 1261.5985890924. The cubic root of 1591631 is about 116.7564270680.

It can be divided in two parts, 1591 and 631, that added together give a palindrome (2222).

The spelling of 1591631 in words is "one million, five hundred ninety-one thousand, six hundred thirty-one".