2170921 has 4 divisors (see below), whose sum is σ = 2285200. Its totient is φ = 2056644.

The previous prime is 2170919. The next prime is 2170937. The reversal of 2170921 is 1290712.

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 2170921 - 2¹ = 2170919 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2170892 and 2170901.

It is not an unprimeable number, because it can be changed into a prime (2170121) 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, 57111 + ... + 57148.

It is an arithmetic number, because the mean of its divisors is an integer number (571300).

2^2170921 is an apocalyptic number.

It is an amenable number.

2170921 is a deficient number, since it is larger than the sum of its proper divisors (114279).

2170921 is a wasteful number, since it uses less digits than its factorization.

2170921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114278.

The product of its (nonzero) digits is 252, while the sum is 22.

The square root of 2170921 is about 1473.4045608725. The cubic root of 2170921 is about 129.4835725002.

The spelling of 2170921 in words is "two million, one hundred seventy thousand, nine hundred twenty-one".