81085479 has 16 divisors (see below), whose sum is σ = 113425920. Its totient is φ = 51453920.

The previous prime is 81085471. The next prime is 81085489. The reversal of 81085479 is 97458018.

It is a cyclic number.

It is not a de Polignac number, because 81085479 - 2³ = 81085471 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81085479.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81085471) 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, 387 + ... + 12740.

It is an arithmetic number, because the mean of its divisors is an integer number (7089120).

Almost surely, 2^81085479 is an apocalyptic number.

81085479 is a deficient number, since it is larger than the sum of its proper divisors (32340441).

81085479 is a wasteful number, since it uses less digits than its factorization.

81085479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13230.

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

The square root of 81085479 is about 9004.7475811374. The cubic root of 81085479 is about 432.8270176479.

The spelling of 81085479 in words is "eighty-one million, eighty-five thousand, four hundred seventy-nine".