81880039 has 2 divisors, whose sum is σ = 81880040. Its totient is φ = 81880038.

The previous prime is 81880033. The next prime is 81880061. The reversal of 81880039 is 93008818.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81880039 - 2¹⁹ = 81355751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81880033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40940019 + 40940020.

It is an arithmetic number, because the mean of its divisors is an integer number (40940020).

Almost surely, 2^81880039 is an apocalyptic number.

81880039 is a deficient number, since it is larger than the sum of its proper divisors (1).

81880039 is an equidigital number, since it uses as much as digits as its factorization.

81880039 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 81880039 is about 9048.7589756828. The cubic root of 81880039 is about 434.2361881313.

The spelling of 81880039 in words is "eighty-one million, eight hundred eighty thousand, thirty-nine".