81545109 has 4 divisors (see below), whose sum is σ = 108726816. Its totient is φ = 54363404.

The previous prime is 81545099. The next prime is 81545137. The reversal of 81545109 is 90154518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81545109 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81545109.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81545179) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13590849 + ... + 13590854.

It is an arithmetic number, because the mean of its divisors is an integer number (27181704).

Almost surely, 2^81545109 is an apocalyptic number.

It is an amenable number.

81545109 is a deficient number, since it is larger than the sum of its proper divisors (27181707).

81545109 is a wasteful number, since it uses less digits than its factorization.

81545109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27181706.

The product of its (nonzero) digits is 7200, while the sum is 33.

The square root of 81545109 is about 9030.2330534710. The cubic root of 81545109 is about 433.6432984776.

The spelling of 81545109 in words is "eighty-one million, five hundred forty-five thousand, one hundred nine".