26311759681 has 3 divisors (see below), whose sum is σ = 26311921891. Its totient is φ = 26311597472.

The previous prime is 26311759613. The next prime is 26311759697. The reversal of 26311759681 is 18695711362.

The square root of 26311759681 is 162209.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18695711362 = 2 ⋅9347855681.

It can be written as a sum of positive squares in only one way, i.e., 24897999681 + 1413760000 = 157791^2 + 37600^2 .

It is not a de Polignac number, because 26311759681 - 2¹³ = 26311751489 is a prime.

It is a super-2 number, since 2×26311759681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26311759081) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 81105 + ... + 243313.

Almost surely, 2^26311759681 is an apocalyptic number.

26311759681 is the 162209-th square number.

26311759681 is the 81105-th centered octagonal number.

It is an amenable number.

26311759681 is a deficient number, since it is larger than the sum of its proper divisors (162210).

26311759681 is an frugal number, since it uses more digits than its factorization.

26311759681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324418 (or 162209 counting only the distinct ones).

The product of its digits is 544320, while the sum is 49.

Multiplying 26311759681 by its sum of digits (49), we get a square (1289276224369 = 1135463²).

The spelling of 26311759681 in words is "twenty-six billion, three hundred eleven million, seven hundred fifty-nine thousand, six hundred eighty-one".