81504791 has 2 divisors, whose sum is σ = 81504792. Its totient is φ = 81504790.

The previous prime is 81504781. The next prime is 81504799. The reversal of 81504791 is 19740518.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81504791 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81504799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40752395 + 40752396.

It is an arithmetic number, because the mean of its divisors is an integer number (40752396).

Almost surely, 2^81504791 is an apocalyptic number.

81504791 is a deficient number, since it is larger than the sum of its proper divisors (1).

81504791 is an equidigital number, since it uses as much as digits as its factorization.

81504791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 35.

The square root of 81504791 is about 9028.0003876828. Note that the first 3 decimals coincide. The cubic root of 81504791 is about 433.5718185611.

The spelling of 81504791 in words is "eighty-one million, five hundred four thousand, seven hundred ninety-one".