81946771 has 2 divisors, whose sum is σ = 81946772. Its totient is φ = 81946770.

The previous prime is 81946759. The next prime is 81946789. The reversal of 81946771 is 17764918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81946771 - 2¹³ = 81938579 is a prime.

It is not a weakly prime, because it can be changed into another prime (81941771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40973385 + 40973386.

It is an arithmetic number, because the mean of its divisors is an integer number (40973386).

Almost surely, 2^81946771 is an apocalyptic number.

81946771 is a deficient number, since it is larger than the sum of its proper divisors (1).

81946771 is an equidigital number, since it uses as much as digits as its factorization.

81946771 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 43.

The square root of 81946771 is about 9052.4455811676. The cubic root of 81946771 is about 434.3541231862.

The spelling of 81946771 in words is "eighty-one million, nine hundred forty-six thousand, seven hundred seventy-one".