81700291 has 2 divisors, whose sum is σ = 81700292. Its totient is φ = 81700290.

The previous prime is 81700277. The next prime is 81700343. The reversal of 81700291 is 19200718.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81700291 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81700231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40850145 + 40850146.

It is an arithmetic number, because the mean of its divisors is an integer number (40850146).

Almost surely, 2^81700291 is an apocalyptic number.

81700291 is a deficient number, since it is larger than the sum of its proper divisors (1).

81700291 is an equidigital number, since it uses as much as digits as its factorization.

81700291 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 81700291 is about 9038.8213280272. The cubic root of 81700291 is about 433.9182015065.

The spelling of 81700291 in words is "eighty-one million, seven hundred thousand, two hundred ninety-one".