26643949909 has 2 divisors, whose sum is σ = 26643949910. Its totient is φ = 26643949908.

The previous prime is 26643949879. The next prime is 26643949933. The reversal of 26643949909 is 90994934662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25813242225 + 830707684 = 160665^2 + 28822^2 .

It is a cyclic number.

It is not a de Polignac number, because 26643949909 - 2⁵ = 26643949877 is a prime.

It is a super-2 number, since 2×26643949909² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (26643949609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13321974954 + 13321974955.

It is an arithmetic number, because the mean of its divisors is an integer number (13321974955).

Almost surely, 2^26643949909 is an apocalyptic number.

It is an amenable number.

26643949909 is a deficient number, since it is larger than the sum of its proper divisors (1).

26643949909 is an equidigital number, since it uses as much as digits as its factorization.

26643949909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22674816, while the sum is 61.

The spelling of 26643949909 in words is "twenty-six billion, six hundred forty-three million, nine hundred forty-nine thousand, nine hundred nine".