2581813 has 6 divisors (see below), whose sum is σ = 2795874. Its totient is φ = 2383056.

The previous prime is 2581771. The next prime is 2581829. The reversal of 2581813 is 3181852.

It can be written as a sum of positive squares in 3 ways, for example, as 154449 + 2427364 = 393^2 + 1558^2 .

It is not a de Polignac number, because 2581813 - 2¹³ = 2573621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2581013) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7470 + ... + 7807.

It is an arithmetic number, because the mean of its divisors is an integer number (465979).

2^2581813 is an apocalyptic number.

It is an amenable number.

2581813 is a deficient number, since it is larger than the sum of its proper divisors (214061).

2581813 is a wasteful number, since it uses less digits than its factorization.

2581813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15303 (or 15290 counting only the distinct ones).

The product of its digits is 1920, while the sum is 28.

The square root of 2581813 is about 1606.8021035585. The cubic root of 2581813 is about 137.1855159850.

The spelling of 2581813 in words is "two million, five hundred eighty-one thousand, eight hundred thirteen".