81349739 has 2 divisors, whose sum is σ = 81349740. Its totient is φ = 81349738.

The previous prime is 81349733. The next prime is 81349769. The reversal of 81349739 is 93794318.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81349739 - 2⁸ = 81349483 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81349739.

It is not a weakly prime, because it can be changed into another prime (81349733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40674869 + 40674870.

It is an arithmetic number, because the mean of its divisors is an integer number (40674870).

Almost surely, 2^81349739 is an apocalyptic number.

81349739 is a deficient number, since it is larger than the sum of its proper divisors (1).

81349739 is an equidigital number, since it uses as much as digits as its factorization.

81349739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 44.

The square root of 81349739 is about 9019.4090161163. The cubic root of 81349739 is about 433.2967065032.

The spelling of 81349739 in words is "eighty-one million, three hundred forty-nine thousand, seven hundred thirty-nine".