26641561 has 2 divisors, whose sum is σ = 26641562. Its totient is φ = 26641560.

The previous prime is 26641547. The next prime is 26641579. The reversal of 26641561 is 16514662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16040025 + 10601536 = 4005^2 + 3256^2 .

It is a cyclic number.

It is not a de Polignac number, because 26641561 - 2⁵ = 26641529 is a prime.

It is not a weakly prime, because it can be changed into another prime (26641541) 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, 13320780 + 13320781.

It is an arithmetic number, because the mean of its divisors is an integer number (13320781).

Almost surely, 2^26641561 is an apocalyptic number.

It is an amenable number.

26641561 is a deficient number, since it is larger than the sum of its proper divisors (1).

26641561 is an equidigital number, since it uses as much as digits as its factorization.

26641561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 31.

The square root of 26641561 is about 5161.5463768138. The cubic root of 26641561 is about 298.6665297873. Note that the first 3 decimals are identical.

It can be divided in two parts, 2664 and 1561, that added together give a square (4225 = 65²).

The spelling of 26641561 in words is "twenty-six million, six hundred forty-one thousand, five hundred sixty-one".