2159921 has 8 divisors (see below), whose sum is σ = 2234400. Its totient is φ = 2086560.

The previous prime is 2159903. The next prime is 2159923. The reversal of 2159921 is 1299512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2159921 is a prime.

It is a d-powerful number, because it can be written as 2⁹ + 1 + 5⁵ + 9² + 9⁵ + 2²¹ + 1 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2159923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5510 + ... + 5888.

It is an arithmetic number, because the mean of its divisors is an integer number (279300).

2^2159921 is an apocalyptic number.

It is an amenable number.

2159921 is a deficient number, since it is larger than the sum of its proper divisors (74479).

2159921 is a wasteful number, since it uses less digits than its factorization.

2159921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559.

The product of its digits is 1620, while the sum is 29.

The square root of 2159921 is about 1469.6669690784. Note that the first 3 decimals coincide. The cubic root of 2159921 is about 129.2645054536.

The spelling of 2159921 in words is "two million, one hundred fifty-nine thousand, nine hundred twenty-one".