81017205 has 8 divisors (see below), whose sum is σ = 129627552. Its totient is φ = 43209168.

The previous prime is 81017191. The next prime is 81017221. The reversal of 81017205 is 50271018.

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

It is not a de Polignac number, because 81017205 - 2²³ = 72628597 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2700559 + ... + 2700588.

It is an arithmetic number, because the mean of its divisors is an integer number (16203444).

Almost surely, 2^81017205 is an apocalyptic number.

It is an amenable number.

81017205 is a deficient number, since it is larger than the sum of its proper divisors (48610347).

81017205 is a wasteful number, since it uses less digits than its factorization.

81017205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5401155.

The product of its (nonzero) digits is 560, while the sum is 24.

The square root of 81017205 is about 9000.9557825822. The cubic root of 81017205 is about 432.7055033727.

The spelling of 81017205 in words is "eighty-one million, seventeen thousand, two hundred five".