2137561 has 4 divisors (see below), whose sum is σ = 2211300. Its totient is φ = 2063824.

The previous prime is 2137549. The next prime is 2137571. The reversal of 2137561 is 1657312.

2137561 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.

It can be written as a sum of positive squares in 2 ways, for example, as 447561 + 1690000 = 669^2 + 1300^2 .

It is a cyclic number.

It is not a de Polignac number, because 2137561 - 2⁹ = 2137049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2137571) 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, 36826 + ... + 36883.

It is an arithmetic number, because the mean of its divisors is an integer number (552825).

2^2137561 is an apocalyptic number.

It is an amenable number.

2137561 is a deficient number, since it is larger than the sum of its proper divisors (73739).

2137561 is an equidigital number, since it uses as much as digits as its factorization.

2137561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73738.

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

The square root of 2137561 is about 1462.0400131323. The cubic root of 2137561 is about 128.8168986547.

Subtracting from 2137561 its reverse (1657312), we obtain a square (480249 = 693²).

The spelling of 2137561 in words is "two million, one hundred thirty-seven thousand, five hundred sixty-one".