81745039 has 2 divisors, whose sum is σ = 81745040. Its totient is φ = 81745038.

The previous prime is 81745009. The next prime is 81745043. The reversal of 81745039 is 93054718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81745039 - 2⁵ = 81745007 is a prime.

It is a super-2 number, since 2×81745039² = 13364502802223042, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81744989 and 81745007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81745009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40872519 + 40872520.

It is an arithmetic number, because the mean of its divisors is an integer number (40872520).

Almost surely, 2^81745039 is an apocalyptic number.

81745039 is a deficient number, since it is larger than the sum of its proper divisors (1).

81745039 is an equidigital number, since it uses as much as digits as its factorization.

81745039 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 81745039 is about 9041.2963119234. The cubic root of 81745039 is about 433.9974073762.

The spelling of 81745039 in words is "eighty-one million, seven hundred forty-five thousand, thirty-nine".