81030509 has 8 divisors (see below), whose sum is σ = 94124928. Its totient is φ = 68315760.

The previous prime is 81030503. The next prime is 81030557. The reversal of 81030509 is 90503018.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81030509 - 2⁸ = 81030253 is a prime.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81030503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 94457 + ... + 95310.

It is an arithmetic number, because the mean of its divisors is an integer number (11765616).

Almost surely, 2^81030509 is an apocalyptic number.

It is an amenable number.

81030509 is a deficient number, since it is larger than the sum of its proper divisors (13094419).

81030509 is a wasteful number, since it uses less digits than its factorization.

81030509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189835.

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

The square root of 81030509 is about 9001.6947848725. The cubic root of 81030509 is about 432.7291872266.

The spelling of 81030509 in words is "eighty-one million, thirty thousand, five hundred nine".