81005039 has 2 divisors, whose sum is σ = 81005040. Its totient is φ = 81005038.

The previous prime is 81005009. The next prime is 81005059. The reversal of 81005039 is 93050018.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81005039 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81004999 and 81005017.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81005009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40502519 + 40502520.

It is an arithmetic number, because the mean of its divisors is an integer number (40502520).

Almost surely, 2^81005039 is an apocalyptic number.

81005039 is a deficient number, since it is larger than the sum of its proper divisors (1).

81005039 is an equidigital number, since it uses as much as digits as its factorization.

81005039 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 81005039 is about 9000.2799400908. The cubic root of 81005039 is about 432.6838431229.

The spelling of 81005039 in words is "eighty-one million, five thousand, thirty-nine".