26181391 has 6 divisors (see below), whose sum is σ = 27055392. Its totient is φ = 25309260.

The previous prime is 26181371. The next prime is 26181401. The reversal of 26181391 is 19318162.

It is not a de Polignac number, because 26181391 - 2⁷ = 26181263 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26181371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 28030 + ... + 28948.

It is an arithmetic number, because the mean of its divisors is an integer number (4509232).

Almost surely, 2^26181391 is an apocalyptic number.

26181391 is a deficient number, since it is larger than the sum of its proper divisors (874001).

26181391 is an frugal number, since it uses more digits than its factorization.

26181391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1869 (or 950 counting only the distinct ones).

The product of its digits is 2592, while the sum is 31.

The square root of 26181391 is about 5116.7754494408. The cubic root of 26181391 is about 296.9369469401.

Multiplying 26181391 by its sum of digits (31), we get a square (811623121 = 28489²).

26181391 divided by its sum of digits (31) gives a square (844561 = 919²).

The spelling of 26181391 in words is "twenty-six million, one hundred eighty-one thousand, three hundred ninety-one".