81512205 has 8 divisors (see below), whose sum is σ = 130419552. Its totient is φ = 43473168.

The previous prime is 81512201. The next prime is 81512231. The reversal of 81512205 is 50221518.

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

It is not a de Polignac number, because 81512205 - 2² = 81512201 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81512201) 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, 2717059 + ... + 2717088.

It is an arithmetic number, because the mean of its divisors is an integer number (16302444).

Almost surely, 2^81512205 is an apocalyptic number.

It is an amenable number.

81512205 is a deficient number, since it is larger than the sum of its proper divisors (48907347).

81512205 is a wasteful number, since it uses less digits than its factorization.

81512205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5434155.

The product of its (nonzero) digits is 800, while the sum is 24.

The square root of 81512205 is about 9028.4109897589. The cubic root of 81512205 is about 433.5849646349.

The spelling of 81512205 in words is "eighty-one million, five hundred twelve thousand, two hundred five".