2171521 has 8 divisors (see below), whose sum is σ = 2391264. Its totient is φ = 1955520.

The previous prime is 2171509. The next prime is 2171527. The reversal of 2171521 is 1251712.

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

It is a cyclic number.

It is not a de Polignac number, because 2171521 - 2¹⁷ = 2040449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2171527) 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, 370 + ... + 2116.

It is an arithmetic number, because the mean of its divisors is an integer number (298908).

2^2171521 is an apocalyptic number.

It is an amenable number.

2171521 is a deficient number, since it is larger than the sum of its proper divisors (219743).

2171521 is a wasteful number, since it uses less digits than its factorization.

2171521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1871.

The product of its digits is 140, while the sum is 19.

The square root of 2171521 is about 1473.6081568721. The cubic root of 2171521 is about 129.4955003083.

It can be divided in two parts, 21715 and 21, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 2171521 in words is "two million, one hundred seventy-one thousand, five hundred twenty-one".