26581381 has 4 divisors (see below), whose sum is σ = 26593164. Its totient is φ = 26569600.

The previous prime is 26581369. The next prime is 26581391. The reversal of 26581381 is 18318562.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18318562 = 2 ⋅9159281.

It can be written as a sum of positive squares in 2 ways, for example, as 17181025 + 9400356 = 4145^2 + 3066^2 .

It is a cyclic number.

It is not a de Polignac number, because 26581381 - 2¹⁹ = 26057093 is a prime.

It is a super-2 number, since 2×26581381² = 1413139631734322, 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 (26581351) 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, 1330 + ... + 7411.

It is an arithmetic number, because the mean of its divisors is an integer number (6648291).

Almost surely, 2^26581381 is an apocalyptic number.

It is an amenable number.

26581381 is a deficient number, since it is larger than the sum of its proper divisors (11783).

26581381 is an equidigital number, since it uses as much as digits as its factorization.

26581381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11782.

The product of its digits is 11520, while the sum is 34.

The square root of 26581381 is about 5155.7134326881. The cubic root of 26581381 is about 298.4414766299.

It can be divided in two parts, 26581 and 381, that added together give a palindrome (26962).

The spelling of 26581381 in words is "twenty-six million, five hundred eighty-one thousand, three hundred eighty-one".