26551981 has 4 divisors (see below), whose sum is σ = 26666172. Its totient is φ = 26437792.

The previous prime is 26551957. The next prime is 26552021. The reversal of 26551981 is 18915562.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18915562 = 2 ⋅9457781.

It can be written as a sum of positive squares in 2 ways, for example, as 15602500 + 10949481 = 3950^2 + 3309^2 .

It is a cyclic number.

It is not a de Polignac number, because 26551981 - 2⁷ = 26551853 is a prime.

It is a super-2 number, since 2×26551981² = 1410015390048722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 26551981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (26551901) 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 3 ways as a sum of consecutive naturals, for example, 56746 + ... + 57211.

It is an arithmetic number, because the mean of its divisors is an integer number (6666543).

Almost surely, 2^26551981 is an apocalyptic number.

It is an amenable number.

26551981 is a deficient number, since it is larger than the sum of its proper divisors (114191).

26551981 is a wasteful number, since it uses less digits than its factorization.

26551981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114190.

The product of its digits is 21600, while the sum is 37.

The square root of 26551981 is about 5152.8614380750. The cubic root of 26551981 is about 298.3314069002.

The spelling of 26551981 in words is "twenty-six million, five hundred fifty-one thousand, nine hundred eighty-one".