26561245021 has 4 divisors (see below), whose sum is σ = 26598708700. Its totient is φ = 26523781344.

The previous prime is 26561244929. The next prime is 26561245103. The reversal of 26561245021 is 12054216562.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1189215225 + 25372029796 = 34485^2 + 159286^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-26561245021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26561245121) 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, 18730776 + ... + 18732193.

It is an arithmetic number, because the mean of its divisors is an integer number (6649677175).

Almost surely, 2^26561245021 is an apocalyptic number.

It is an amenable number.

26561245021 is a deficient number, since it is larger than the sum of its proper divisors (37463679).

26561245021 is an equidigital number, since it uses as much as digits as its factorization.

26561245021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37463678.

The product of its (nonzero) digits is 28800, while the sum is 34.

The spelling of 26561245021 in words is "twenty-six billion, five hundred sixty-one million, two hundred forty-five thousand, twenty-one".