81405241 has 4 divisors (see below), whose sum is σ = 81423952. Its totient is φ = 81386532.

The previous prime is 81405229. The next prime is 81405301. The reversal of 81405241 is 14250418.

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 not a de Polignac number, because 81405241 - 2⁵ = 81405209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81405341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 970 + ... + 12796.

It is an arithmetic number, because the mean of its divisors is an integer number (20355988).

Almost surely, 2^81405241 is an apocalyptic number.

It is an amenable number.

81405241 is a deficient number, since it is larger than the sum of its proper divisors (18711).

81405241 is a wasteful number, since it uses less digits than its factorization.

81405241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18710.

The product of its (nonzero) digits is 1280, while the sum is 25.

The square root of 81405241 is about 9022.4853006253. The cubic root of 81405241 is about 433.3952250191.

Adding to 81405241 its reverse (14250418), we get a palindrome (95655659).

The spelling of 81405241 in words is "eighty-one million, four hundred five thousand, two hundred forty-one".