81186797 has 4 divisors (see below), whose sum is σ = 81931740. Its totient is φ = 80441856.

The previous prime is 81186751. The next prime is 81186821. The reversal of 81186797 is 79768118.

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 74063236 + 7123561 = 8606^2 + 2669^2 .

It is a cyclic number.

It is not a de Polignac number, because 81186797 - 2⁶ = 81186733 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 (81186097) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 372308 + ... + 372525.

It is an arithmetic number, because the mean of its divisors is an integer number (20482935).

Almost surely, 2^81186797 is an apocalyptic number.

It is an amenable number.

81186797 is a deficient number, since it is larger than the sum of its proper divisors (744943).

81186797 is a wasteful number, since it uses less digits than its factorization.

81186797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 744942.

The product of its digits is 169344, while the sum is 47.

The square root of 81186797 is about 9010.3716349549. The cubic root of 81186797 is about 433.0072180809.

The spelling of 81186797 in words is "eighty-one million, one hundred eighty-six thousand, seven hundred ninety-seven".