81294791 has 4 divisors (see below), whose sum is σ = 81588552. Its totient is φ = 81001032.

The previous prime is 81294779. The next prime is 81294821. The reversal of 81294791 is 19749218.

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

It is a cyclic number.

It is not a de Polignac number, because 81294791 - 2⁶ = 81294727 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 (81294751) 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, 146465 + ... + 147018.

It is an arithmetic number, because the mean of its divisors is an integer number (20397138).

Almost surely, 2^81294791 is an apocalyptic number.

81294791 is a deficient number, since it is larger than the sum of its proper divisors (293761).

81294791 is a wasteful number, since it uses less digits than its factorization.

81294791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293760.

The product of its digits is 36288, while the sum is 41.

The square root of 81294791 is about 9016.3624039853. The cubic root of 81294791 is about 433.1991272103.

The spelling of 81294791 in words is "eighty-one million, two hundred ninety-four thousand, seven hundred ninety-one".