81740791 has 4 divisors (see below), whose sum is σ = 89171784. Its totient is φ = 74309800.

The previous prime is 81740779. The next prime is 81740803. The reversal of 81740791 is 19704718.

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

It is an interprime number because it is at equal distance from previous prime (81740779) and next prime (81740803).

It is a cyclic number.

It is not a de Polignac number, because 81740791 - 2⁵ = 81740759 is a prime.

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 81740791.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81740731) 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, 3715480 + ... + 3715501.

It is an arithmetic number, because the mean of its divisors is an integer number (22292946).

Almost surely, 2^81740791 is an apocalyptic number.

81740791 is a deficient number, since it is larger than the sum of its proper divisors (7430993).

81740791 is a wasteful number, since it uses less digits than its factorization.

81740791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7430992.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 81740791 is about 9041.0613868063. The cubic root of 81740791 is about 433.9898894769.

The spelling of 81740791 in words is "eighty-one million, seven hundred forty thousand, seven hundred ninety-one".