81272797 has 6 divisors (see below), whose sum is σ = 82838042. Its totient is φ = 79736592.

The previous prime is 81272773. The next prime is 81272827. The reversal of 81272797 is 79727218.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 28579716 + 52693081 = 5346^2 + 7259^2 .

It is not a de Polignac number, because 81272797 - 2¹⁹ = 80748509 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 (81272717) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11658 + ... + 17275.

Almost surely, 2^81272797 is an apocalyptic number.

It is an amenable number.

81272797 is a deficient number, since it is larger than the sum of its proper divisors (1565245).

81272797 is an equidigital number, since it uses as much as digits as its factorization.

81272797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29039 (or 28986 counting only the distinct ones).

The product of its digits is 98784, while the sum is 43.

The square root of 81272797 is about 9015.1426500084. The cubic root of 81272797 is about 433.1600568884.

The spelling of 81272797 in words is "eighty-one million, two hundred seventy-two thousand, seven hundred ninety-seven".