2152181 has 4 divisors (see below), whose sum is σ = 2156364. Its totient is φ = 2148000.

The previous prime is 2152169. The next prime is 2152201. The reversal of 2152181 is 1812512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1865956 + 286225 = 1366^2 + 535^2 .

It is a cyclic number.

It is not a de Polignac number, because 2152181 - 2¹⁰ = 2151157 is a prime.

It is a super-2 number, since 2×2152181² = 9263766113522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2152481) 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, 1190 + ... + 2391.

It is an arithmetic number, because the mean of its divisors is an integer number (539091).

2^2152181 is an apocalyptic number.

It is an amenable number.

2152181 is a deficient number, since it is larger than the sum of its proper divisors (4183).

2152181 is an equidigital number, since it uses as much as digits as its factorization.

2152181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4182.

The product of its digits is 160, while the sum is 20.

The square root of 2152181 is about 1467.0313561748. The cubic root of 2152181 is about 129.1099157331.

Adding to 2152181 its reverse (1812512), we get a palindrome (3964693).

The spelling of 2152181 in words is "two million, one hundred fifty-two thousand, one hundred eighty-one".