81275747 has 4 divisors (see below), whose sum is σ = 92886576. Its totient is φ = 69664920.

The previous prime is 81275743. The next prime is 81275801. The reversal of 81275747 is 74757218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74757218 = 2 ⋅37378609.

It is a cyclic number.

It is not a de Polignac number, because 81275747 - 2² = 81275743 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81275743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5805404 + ... + 5805417.

It is an arithmetic number, because the mean of its divisors is an integer number (23221644).

Almost surely, 2^81275747 is an apocalyptic number.

81275747 is a deficient number, since it is larger than the sum of its proper divisors (11610829).

81275747 is a wasteful number, since it uses less digits than its factorization.

81275747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11610828.

The product of its digits is 109760, while the sum is 41.

The square root of 81275747 is about 9015.3062621300. The cubic root of 81275747 is about 433.1652977019.

The spelling of 81275747 in words is "eighty-one million, two hundred seventy-five thousand, seven hundred forty-seven".