2181457 has 4 divisors (see below), whose sum is σ = 2309796. Its totient is φ = 2053120.

The previous prime is 2181449. The next prime is 2181461. The reversal of 2181457 is 7541812.

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 1252161 + 929296 = 1119^2 + 964^2 .

It is a cyclic number.

It is not a de Polignac number, because 2181457 - 2³ = 2181449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2181857) 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, 64144 + ... + 64177.

It is an arithmetic number, because the mean of its divisors is an integer number (577449).

2^2181457 is an apocalyptic number.

It is an amenable number.

2181457 is a deficient number, since it is larger than the sum of its proper divisors (128339).

2181457 is a wasteful number, since it uses less digits than its factorization.

2181457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128338.

The product of its digits is 2240, while the sum is 28.

The square root of 2181457 is about 1476.9756260684. The cubic root of 2181457 is about 129.6927061441.

The spelling of 2181457 in words is "two million, one hundred eighty-one thousand, four hundred fifty-seven".