81541915 has 16 divisors (see below), whose sum is σ = 120431808. Its totient is φ = 51613056.

The previous prime is 81541909. The next prime is 81541927. The reversal of 81541915 is 51914518.

It is a cyclic number.

It is not a de Polignac number, because 81541915 - 2⁵ = 81541883 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89152 + ... + 90061.

It is an arithmetic number, because the mean of its divisors is an integer number (7526988).

Almost surely, 2^81541915 is an apocalyptic number.

81541915 is a deficient number, since it is larger than the sum of its proper divisors (38889893).

81541915 is a wasteful number, since it uses less digits than its factorization.

81541915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179238.

The product of its digits is 7200, while the sum is 34.

The square root of 81541915 is about 9030.0562013755. The cubic root of 81541915 is about 433.6376366838.

The spelling of 81541915 in words is "eighty-one million, five hundred forty-one thousand, nine hundred fifteen".