81272801 has 16 divisors (see below), whose sum is σ = 88150608. Its totient is φ = 74649600.

The previous prime is 81272773. The next prime is 81272827. The reversal of 81272801 is 10827218.

It can be written as a sum of positive squares in 8 ways, for example, as 35046400 + 46226401 = 5920^2 + 6799^2 .

It is a cyclic number.

It is not a de Polignac number, because 81272801 - 2¹⁰ = 81271777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81275801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 187481 + ... + 187913.

It is an arithmetic number, because the mean of its divisors is an integer number (5509413).

Almost surely, 2^81272801 is an apocalyptic number.

81272801 is the 7361-st pentagonal number.

It is an amenable number.

81272801 is a deficient number, since it is larger than the sum of its proper divisors (6877807).

81272801 is a wasteful number, since it uses less digits than its factorization.

81272801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 692.

The product of its (nonzero) digits is 1792, while the sum is 29.

The square root of 81272801 is about 9015.1428718573. The cubic root of 81272801 is about 433.1600639947.

The spelling of 81272801 in words is "eighty-one million, two hundred seventy-two thousand, eight hundred one".