2145581 has 4 divisors (see below), whose sum is σ = 2156892. Its totient is φ = 2134272.

The previous prime is 2145551. The next prime is 2145617. The reversal of 2145581 is 1855412.

2145581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 366025 + 1779556 = 605^2 + 1334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2145581 is a prime.

It is a super-2 number, since 2×2145581² = 9207035655122, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2145581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2145551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5366 + ... + 5751.

It is an arithmetic number, because the mean of its divisors is an integer number (539223).

2^2145581 is an apocalyptic number.

It is an amenable number.

2145581 is a deficient number, since it is larger than the sum of its proper divisors (11311).

2145581 is a wasteful number, since it uses less digits than its factorization.

2145581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11310.

The product of its digits is 1600, while the sum is 26.

The square root of 2145581 is about 1464.7801882876. The cubic root of 2145581 is about 128.9778020014.

The spelling of 2145581 in words is "two million, one hundred forty-five thousand, five hundred eighty-one".