81092551 has 4 divisors (see below), whose sum is σ = 85360600. Its totient is φ = 76824504.

The previous prime is 81092527. The next prime is 81092569. The reversal of 81092551 is 15529018.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15529018 = 2 ⋅7764509.

It is a cyclic number.

It is not a de Polignac number, because 81092551 - 2⁷ = 81092423 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81092521) 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 3 ways as a sum of consecutive naturals, for example, 2133996 + ... + 2134033.

It is an arithmetic number, because the mean of its divisors is an integer number (21340150).

Almost surely, 2^81092551 is an apocalyptic number.

81092551 is a deficient number, since it is larger than the sum of its proper divisors (4268049).

81092551 is a wasteful number, since it uses less digits than its factorization.

81092551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4268048.

The product of its (nonzero) digits is 3600, while the sum is 31.

The square root of 81092551 is about 9005.1402543214. The cubic root of 81092551 is about 432.8396005161.

The spelling of 81092551 in words is "eighty-one million, ninety-two thousand, five hundred fifty-one".