2151689 has 4 divisors (see below), whose sum is σ = 2154624. Its totient is φ = 2148756.

The previous prime is 2151683. The next prime is 2151701. The reversal of 2151689 is 9861512.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2151689 - 2⁸ = 2151433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2151683) 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, 704 + ... + 2190.

It is an arithmetic number, because the mean of its divisors is an integer number (538656).

2^2151689 is an apocalyptic number.

It is an amenable number.

2151689 is a deficient number, since it is larger than the sum of its proper divisors (2935).

2151689 is a wasteful number, since it uses less digits than its factorization.

2151689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2934.

The product of its digits is 4320, while the sum is 32.

The square root of 2151689 is about 1466.8636610128. The cubic root of 2151689 is about 129.1000765793.

The spelling of 2151689 in words is "two million, one hundred fifty-one thousand, six hundred eighty-nine".