81881207 has 2 divisors, whose sum is σ = 81881208. Its totient is φ = 81881206.

The previous prime is 81881171. The next prime is 81881213. The reversal of 81881207 is 70218818.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81881207 - 2⁶ = 81881143 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 (81881287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40940603 + 40940604.

It is an arithmetic number, because the mean of its divisors is an integer number (40940604).

Almost surely, 2^81881207 is an apocalyptic number.

81881207 is a deficient number, since it is larger than the sum of its proper divisors (1).

81881207 is an equidigital number, since it uses as much as digits as its factorization.

81881207 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7168, while the sum is 35.

The square root of 81881207 is about 9048.8235146896. The cubic root of 81881207 is about 434.2382528814.

The spelling of 81881207 in words is "eighty-one million, eight hundred eighty-one thousand, two hundred seven".