2731561 has 4 divisors (see below), whose sum is σ = 3121792. Its totient is φ = 2341332.

The previous prime is 2731559. The next prime is 2731571. The reversal of 2731561 is 1651372.

2731561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 2731561 - 2¹ = 2731559 is a prime.

It is a super-2 number, since 2×2731561² = 14922850993442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2731501) 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 in 3 ways as a sum of consecutive naturals, for example, 195105 + ... + 195118.

It is an arithmetic number, because the mean of its divisors is an integer number (780448).

2^2731561 is an apocalyptic number.

It is an amenable number.

2731561 is a deficient number, since it is larger than the sum of its proper divisors (390231).

2731561 is an equidigital number, since it uses as much as digits as its factorization.

2731561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390230.

The product of its digits is 1260, while the sum is 25.

The square root of 2731561 is about 1652.7434767682. The cubic root of 2731561 is about 139.7881319135.

The spelling of 2731561 in words is "two million, seven hundred thirty-one thousand, five hundred sixty-one".