2123561 has 4 divisors (see below), whose sum is σ = 2316624. Its totient is φ = 1930500.

The previous prime is 2123557. The next prime is 2123581. The reversal of 2123561 is 1653212.

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 2123561 - 2² = 2123557 is a prime.

It is a super-2 number, since 2×2123561² = 9019022641442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2123581) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96515 + ... + 96536.

It is an arithmetic number, because the mean of its divisors is an integer number (579156).

2^2123561 is an apocalyptic number.

It is an amenable number.

2123561 is a deficient number, since it is larger than the sum of its proper divisors (193063).

2123561 is a wasteful number, since it uses less digits than its factorization.

2123561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193062.

The product of its digits is 360, while the sum is 20.

The square root of 2123561 is about 1457.2443171960. The cubic root of 2123561 is about 128.5350527900.

Adding to 2123561 its reverse (1653212), we get a palindrome (3776773).

It can be divided in two parts, 212 and 3561, that added together give a palindrome (3773).

The spelling of 2123561 in words is "two million, one hundred twenty-three thousand, five hundred sixty-one".