2015581 has 4 divisors (see below), whose sum is σ = 2033532. Its totient is φ = 1997632.

The previous prime is 2015579. The next prime is 2015599. The reversal of 2015581 is 1855102.

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 749956 + 1265625 = 866^2 + 1125^2 .

It is a cyclic number.

It is not a de Polignac number, because 2015581 - 2¹ = 2015579 is a prime.

It is a super-2 number, since 2×2015581² = 8125133535122, 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 (2015081) 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, 8806 + ... + 9031.

It is an arithmetic number, because the mean of its divisors is an integer number (508383).

2^2015581 is an apocalyptic number.

It is an amenable number.

2015581 is a deficient number, since it is larger than the sum of its proper divisors (17951).

2015581 is a wasteful number, since it uses less digits than its factorization.

2015581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17950.

The product of its (nonzero) digits is 400, while the sum is 22.

The square root of 2015581 is about 1419.7115904295. The cubic root of 2015581 is about 126.3184395125.

The spelling of 2015581 in words is "two million, fifteen thousand, five hundred eighty-one".