26181981 has 64 divisors (see below), whose sum is σ = 48844800. Its totient is φ = 13514688.

The previous prime is 26181973. The next prime is 26181997. The reversal of 26181981 is 18918162.

It is not a de Polignac number, because 26181981 - 2³ = 26181973 is a prime.

It is a super-2 number, since 2×26181981² = 1370992258168722, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26181941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 82435 + ... + 82751.

It is an arithmetic number, because the mean of its divisors is an integer number (763200).

Almost surely, 2^26181981 is an apocalyptic number.

26181981 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

26181981 is a deficient number, since it is larger than the sum of its proper divisors (22662819).

26181981 is a wasteful number, since it uses less digits than its factorization.

26181981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375 (or 369 counting only the distinct ones).

The product of its digits is 6912, while the sum is 36.

The square root of 26181981 is about 5116.8331026134. The cubic root of 26181981 is about 296.9391774236.

The spelling of 26181981 in words is "twenty-six million, one hundred eighty-one thousand, nine hundred eighty-one".