2631581 has 2 divisors, whose sum is σ = 2631582. Its totient is φ = 2631580.

The previous prime is 2631553. The next prime is 2631631. The reversal of 2631581 is 1851362.

2631581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1865956 + 765625 = 1366^2 + 875^2 .

It is a cyclic number.

It is not a de Polignac number, because 2631581 - 2¹⁰ = 2630557 is a prime.

It is a super-2 number, since 2×2631581² = 13850437119122, 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 2631581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2631511) 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, 1315790 + 1315791.

It is an arithmetic number, because the mean of its divisors is an integer number (1315791).

2^2631581 is an apocalyptic number.

It is an amenable number.

2631581 is a deficient number, since it is larger than the sum of its proper divisors (1).

2631581 is an equidigital number, since it uses as much as digits as its factorization.

2631581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 26.

The square root of 2631581 is about 1622.2148439710. The cubic root of 2631581 is about 138.0613918543.

The spelling of 2631581 in words is "two million, six hundred thirty-one thousand, five hundred eighty-one".