81772241 has 4 divisors (see below), whose sum is σ = 81827184. Its totient is φ = 81717300.

The previous prime is 81772217. The next prime is 81772247. The reversal of 81772241 is 14227718.

It is a happy number.

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 81772241 - 2²⁶ = 14663377 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81772198 and 81772207.

It is not an unprimeable number, because it can be changed into a prime (81772247) 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, 25175 + ... + 28236.

It is an arithmetic number, because the mean of its divisors is an integer number (20456796).

Almost surely, 2^81772241 is an apocalyptic number.

It is an amenable number.

81772241 is a deficient number, since it is larger than the sum of its proper divisors (54943).

81772241 is a wasteful number, since it uses less digits than its factorization.

81772241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54942.

The product of its digits is 6272, while the sum is 32.

The square root of 81772241 is about 9042.8005064803. The cubic root of 81772241 is about 434.0455419515.

Adding to 81772241 its reverse (14227718), we get a palindrome (95999959).

The spelling of 81772241 in words is "eighty-one million, seven hundred seventy-two thousand, two hundred forty-one".