2121689 has 4 divisors (see below), whose sum is σ = 2153424. Its totient is φ = 2089956.

The previous prime is 2121683. The next prime is 2121737. The reversal of 2121689 is 9861212.

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 a cyclic number.

It is not a de Polignac number, because 2121689 - 2⁸ = 2121433 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121683) 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, 15767 + ... + 15900.

It is an arithmetic number, because the mean of its divisors is an integer number (538356).

2^2121689 is an apocalyptic number.

It is an amenable number.

2121689 is a deficient number, since it is larger than the sum of its proper divisors (31735).

2121689 is an equidigital number, since it uses as much as digits as its factorization.

2121689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31734.

The product of its digits is 1728, while the sum is 29.

The square root of 2121689 is about 1456.6018673612. The cubic root of 2121689 is about 128.4972721693.

The spelling of 2121689 in words is "two million, one hundred twenty-one thousand, six hundred eighty-nine".