81264881 has 4 divisors (see below), whose sum is σ = 85542000. Its totient is φ = 76987764.

The previous prime is 81264877. The next prime is 81264893. The reversal of 81264881 is 18846218.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18846218 = 2 ⋅9423109.

It is a cyclic number.

It is not a de Polignac number, because 81264881 - 2² = 81264877 is a prime.

It is a super-2 number, since 2×81264881² = 13207961767888322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81264581) 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, 2138531 + ... + 2138568.

It is an arithmetic number, because the mean of its divisors is an integer number (21385500).

Almost surely, 2^81264881 is an apocalyptic number.

It is an amenable number.

81264881 is a deficient number, since it is larger than the sum of its proper divisors (4277119).

81264881 is a wasteful number, since it uses less digits than its factorization.

81264881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4277118.

The product of its digits is 24576, while the sum is 38.

The square root of 81264881 is about 9014.7036002300. The cubic root of 81264881 is about 433.1459931161.

The spelling of 81264881 in words is "eighty-one million, two hundred sixty-four thousand, eight hundred eighty-one".