26091306721 has 2 divisors, whose sum is σ = 26091306722. Its totient is φ = 26091306720.

The previous prime is 26091306713. The next prime is 26091306779. The reversal of 26091306721 is 12760319062.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21974801121 + 4116505600 = 148239^2 + 64160^2 .

It is a cyclic number.

It is not a de Polignac number, because 26091306721 - 2³ = 26091306713 is a prime.

It is not a weakly prime, because it can be changed into another prime (26091306781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13045653360 + 13045653361.

It is an arithmetic number, because the mean of its divisors is an integer number (13045653361).

Almost surely, 2^26091306721 is an apocalyptic number.

It is an amenable number.

26091306721 is a deficient number, since it is larger than the sum of its proper divisors (1).

26091306721 is an equidigital number, since it uses as much as digits as its factorization.

26091306721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27216, while the sum is 37.

The spelling of 26091306721 in words is "twenty-six billion, ninety-one million, three hundred six thousand, seven hundred twenty-one".