81940211 has 2 divisors, whose sum is σ = 81940212. Its totient is φ = 81940210.

The previous prime is 81940171. The next prime is 81940231. The reversal of 81940211 is 11204918.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81940211 - 2¹⁸ = 81678067 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81940231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40970105 + 40970106.

It is an arithmetic number, because the mean of its divisors is an integer number (40970106).

Almost surely, 2^81940211 is an apocalyptic number.

81940211 is a deficient number, since it is larger than the sum of its proper divisors (1).

81940211 is an equidigital number, since it uses as much as digits as its factorization.

81940211 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 81940211 is about 9052.0832408899. The cubic root of 81940211 is about 434.3425325766.

The spelling of 81940211 in words is "eighty-one million, nine hundred forty thousand, two hundred eleven".