81284293 has 4 divisors (see below), whose sum is σ = 86065740. Its totient is φ = 76502848.

The previous prime is 81284257. The next prime is 81284309. The reversal of 81284293 is 39248218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39248218 = 2 ⋅19624109.

It can be written as a sum of positive squares in 2 ways, for example, as 52736644 + 28547649 = 7262^2 + 5343^2 .

It is a cyclic number.

It is not a de Polignac number, because 81284293 - 2²⁵ = 47729861 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 (81285293) 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, 2390698 + ... + 2390731.

It is an arithmetic number, because the mean of its divisors is an integer number (21516435).

Almost surely, 2^81284293 is an apocalyptic number.

It is an amenable number.

81284293 is a deficient number, since it is larger than the sum of its proper divisors (4781447).

81284293 is a wasteful number, since it uses less digits than its factorization.

81284293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4781446.

The product of its digits is 27648, while the sum is 37.

The square root of 81284293 is about 9015.7802213674. The cubic root of 81284293 is about 433.1804793562.

It can be divided in two parts, 8128 and 4293, that added together give a palindrome (12421).

The spelling of 81284293 in words is "eighty-one million, two hundred eighty-four thousand, two hundred ninety-three".