81542441 has 4 divisors (see below), whose sum is σ = 81724500. Its totient is φ = 81360384.

The previous prime is 81542407. The next prime is 81542443. The reversal of 81542441 is 14424518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 14424518 = 2 ⋅7212259.

It can be written as a sum of positive squares in 2 ways, for example, as 48594841 + 32947600 = 6971^2 + 5740^2 .

It is a cyclic number.

It is not a de Polignac number, because 81542441 - 2²² = 77348137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81542443) 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, 90356 + ... + 91253.

It is an arithmetic number, because the mean of its divisors is an integer number (20431125).

Almost surely, 2^81542441 is an apocalyptic number.

It is an amenable number.

81542441 is a deficient number, since it is larger than the sum of its proper divisors (182059).

81542441 is a wasteful number, since it uses less digits than its factorization.

81542441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182058.

The product of its digits is 5120, while the sum is 29.

The square root of 81542441 is about 9030.0853262857. The cubic root of 81542441 is about 433.6385690996.

Adding to 81542441 its reverse (14424518), we get a palindrome (95966959).

The spelling of 81542441 in words is "eighty-one million, five hundred forty-two thousand, four hundred forty-one".