81458709 has 16 divisors (see below), whose sum is σ = 117244800. Its totient is φ = 50152256.

The previous prime is 81458701. The next prime is 81458743. The reversal of 81458709 is 90785418.

It is a cyclic number.

It is not a de Polignac number, because 81458709 - 2³ = 81458701 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81458701) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18354 + ... + 22355.

It is an arithmetic number, because the mean of its divisors is an integer number (7327800).

Almost surely, 2^81458709 is an apocalyptic number.

It is an amenable number.

81458709 is a deficient number, since it is larger than the sum of its proper divisors (35786091).

81458709 is a wasteful number, since it uses less digits than its factorization.

81458709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40764.

The product of its (nonzero) digits is 80640, while the sum is 42.

The square root of 81458709 is about 9025.4478559238. The cubic root of 81458709 is about 433.4900907553.

The spelling of 81458709 in words is "eighty-one million, four hundred fifty-eight thousand, seven hundred nine".