2561631 has 8 divisors (see below), whose sum is σ = 3440640. Its totient is φ = 1695192.

The previous prime is 2561627. The next prime is 2561633. The reversal of 2561631 is 1361652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2561631 - 2² = 2561627 is a prime.

It is a super-2 number, since 2×2561631² = 13123906760322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2561633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2655 + ... + 3488.

It is an arithmetic number, because the mean of its divisors is an integer number (430080).

2^2561631 is an apocalyptic number.

2561631 is a deficient number, since it is larger than the sum of its proper divisors (879009).

2561631 is a wasteful number, since it uses less digits than its factorization.

2561631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6285.

The product of its digits is 1080, while the sum is 24.

The square root of 2561631 is about 1600.5096063442. The cubic root of 2561631 is about 136.8271213454.

The spelling of 2561631 in words is "two million, five hundred sixty-one thousand, six hundred thirty-one".