2157181 has 16 divisors (see below), whose sum is σ = 2528064. Its totient is φ = 1822464.

The previous prime is 2157173. The next prime is 2157187. The reversal of 2157181 is 1817512.

It is a cyclic number.

It is not a de Polignac number, because 2157181 - 2³ = 2157173 is a prime.

It is a super-2 number, since 2×2157181² = 9306859733522, 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 (2157187) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9390 + ... + 9616.

It is an arithmetic number, because the mean of its divisors is an integer number (158004).

2^2157181 is an apocalyptic number.

It is an amenable number.

2157181 is a deficient number, since it is larger than the sum of its proper divisors (370883).

2157181 is a wasteful number, since it uses less digits than its factorization.

2157181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300.

The product of its digits is 560, while the sum is 25.

The square root of 2157181 is about 1468.7344892798. The cubic root of 2157181 is about 129.2098221852.

It can be divided in two parts, 215 and 7181, that added together give a square (7396 = 86²).

The spelling of 2157181 in words is "two million, one hundred fifty-seven thousand, one hundred eighty-one".