81796261 has 4 divisors (see below), whose sum is σ = 82393452. Its totient is φ = 81199072.

The previous prime is 81796249. The next prime is 81796283. The reversal of 81796261 is 16269718.

81796261 = T₇₃₈₃ + T₇₃₈₄ + T₇₃₈₅.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 62489025 + 19307236 = 7905^2 + 4394^2 .

It is a cyclic number.

It is not a de Polignac number, because 81796261 - 2⁷ = 81796133 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81796241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 298390 + ... + 298663.

It is an arithmetic number, because the mean of its divisors is an integer number (20598363).

Almost surely, 2^81796261 is an apocalyptic number.

81796261 is the 7385-th centered triangular number.

It is an amenable number.

81796261 is a deficient number, since it is larger than the sum of its proper divisors (597191).

81796261 is a wasteful number, since it uses less digits than its factorization.

81796261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 597190.

The product of its digits is 36288, while the sum is 40.

The square root of 81796261 is about 9044.1285373440. The cubic root of 81796261 is about 434.0880370294.

The spelling of 81796261 in words is "eighty-one million, seven hundred ninety-six thousand, two hundred sixty-one".