26001581 has 2 divisors, whose sum is σ = 26001582. Its totient is φ = 26001580.

The previous prime is 26001559. The next prime is 26001587. The reversal of 26001581 is 18510062.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14945956 + 11055625 = 3866^2 + 3325^2 .

It is a cyclic number.

It is not a de Polignac number, because 26001581 - 2¹⁸ = 25739437 is a prime.

It is a super-2 number, since 2×26001581² = 1352164428999122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26001587) 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 as a sum of consecutive naturals, namely, 13000790 + 13000791.

It is an arithmetic number, because the mean of its divisors is an integer number (13000791).

Almost surely, 2^26001581 is an apocalyptic number.

It is an amenable number.

26001581 is a deficient number, since it is larger than the sum of its proper divisors (1).

26001581 is an equidigital number, since it uses as much as digits as its factorization.

26001581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 26001581 is about 5099.1745410409. The cubic root of 26001581 is about 296.2556114707.

The spelling of 26001581 in words is "twenty-six million, one thousand, five hundred eighty-one".