81541247 has 4 divisors (see below), whose sum is σ = 82060776. Its totient is φ = 81021720.

The previous prime is 81541237. The next prime is 81541249. The reversal of 81541247 is 74214518.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81541247 - 2¹⁸ = 81279103 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81541249) 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, 259529 + ... + 259842.

It is an arithmetic number, because the mean of its divisors is an integer number (20515194).

Almost surely, 2^81541247 is an apocalyptic number.

81541247 is a deficient number, since it is larger than the sum of its proper divisors (519529).

81541247 is a wasteful number, since it uses less digits than its factorization.

81541247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 519528.

The product of its digits is 8960, while the sum is 32.

The square root of 81541247 is about 9030.0192137116. The cubic root of 81541247 is about 433.6364525454.

The spelling of 81541247 in words is "eighty-one million, five hundred forty-one thousand, two hundred forty-seven".