2501581 has 4 divisors (see below), whose sum is σ = 2505664. Its totient is φ = 2497500.

The previous prime is 2501573. The next prime is 2501591. The reversal of 2501581 is 1851052.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2501581 - 2³ = 2501573 is a prime.

It is a super-2 number, since 2×2501581² = 12515814999122, 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 (2501501) 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, 915 + ... + 2416.

It is an arithmetic number, because the mean of its divisors is an integer number (626416).

2^2501581 is an apocalyptic number.

It is an amenable number.

2501581 is a deficient number, since it is larger than the sum of its proper divisors (4083).

2501581 is an equidigital number, since it uses as much as digits as its factorization.

2501581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4082.

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

The square root of 2501581 is about 1581.6387071642. The cubic root of 2501581 is about 135.7494847626.

The spelling of 2501581 in words is "two million, five hundred one thousand, five hundred eighty-one".