81541641 has 4 divisors (see below), whose sum is σ = 108722192. Its totient is φ = 54361092.

The previous prime is 81541619. The next prime is 81541679. The reversal of 81541641 is 14614518.

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 not a de Polignac number, because 81541641 - 2⁵ = 81541609 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81541599 and 81541608.

It is not an unprimeable number, because it can be changed into a prime (81541541) 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, 13590271 + ... + 13590276.

It is an arithmetic number, because the mean of its divisors is an integer number (27180548).

Almost surely, 2^81541641 is an apocalyptic number.

It is an amenable number.

81541641 is a deficient number, since it is larger than the sum of its proper divisors (27180551).

81541641 is a wasteful number, since it uses less digits than its factorization.

81541641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27180550.

The product of its digits is 3840, while the sum is 30.

The square root of 81541641 is about 9030.0410298071. The cubic root of 81541641 is about 433.6371509751.

The spelling of 81541641 in words is "eighty-one million, five hundred forty-one thousand, six hundred forty-one".