26561218957 has 12 divisors (see below), whose sum is σ = 33274494876. Its totient is φ = 21015469440.

The previous prime is 26561218951. The next prime is 26561218963. The reversal of 26561218957 is 75981216562.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (26561218951) and next prime (26561218963).

It can be written as a sum of positive squares in 2 ways, for example, as 16773876196 + 9787342761 = 129514^2 + 98931^2 .

It is not a de Polignac number, because 26561218957 - 2¹¹ = 26561216909 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26561218951) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20848044 + ... + 20849317.

It is an arithmetic number, because the mean of its divisors is an integer number (2772874573).

Almost surely, 2^26561218957 is an apocalyptic number.

It is an amenable number.

26561218957 is a deficient number, since it is larger than the sum of its proper divisors (6713275919).

26561218957 is a wasteful number, since it uses less digits than its factorization.

26561218957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41697388 (or 41697381 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 52.

The spelling of 26561218957 in words is "twenty-six billion, five hundred sixty-one million, two hundred eighteen thousand, nine hundred fifty-seven".