26671564391 has 4 divisors (see below), whose sum is σ = 26671891632. Its totient is φ = 26671237152.

The previous prime is 26671564379. The next prime is 26671564429. The reversal of 26671564391 is 19346517662.

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: 19346517662 = 2 ⋅9673258831.

It is a cyclic number.

It is not a de Polignac number, because 26671564391 - 2²² = 26667370087 is a prime.

It is a super-2 number, since 2×26671564391² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26671564321) 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, 66815 + ... + 240431.

It is an arithmetic number, because the mean of its divisors is an integer number (6667972908).

Almost surely, 2^26671564391 is an apocalyptic number.

26671564391 is a deficient number, since it is larger than the sum of its proper divisors (327241).

26671564391 is a wasteful number, since it uses less digits than its factorization.

26671564391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327240.

The product of its digits is 1632960, while the sum is 50.

The spelling of 26671564391 in words is "twenty-six billion, six hundred seventy-one million, five hundred sixty-four thousand, three hundred ninety-one".