81634771 has 4 divisors (see below), whose sum is σ = 81811552. Its totient is φ = 81457992.

The previous prime is 81634759. The next prime is 81634783. The reversal of 81634771 is 17743618.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (81634759) and next prime (81634783).

It is a cyclic number.

It is not a de Polignac number, because 81634771 - 2¹³ = 81626579 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81634771.

It is not an unprimeable number, because it can be changed into a prime (81634741) 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, 87696 + ... + 88621.

It is an arithmetic number, because the mean of its divisors is an integer number (20452888).

Almost surely, 2^81634771 is an apocalyptic number.

81634771 is a deficient number, since it is larger than the sum of its proper divisors (176781).

81634771 is a wasteful number, since it uses less digits than its factorization.

81634771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176780.

The product of its digits is 28224, while the sum is 37.

The square root of 81634771 is about 9035.1962347256. The cubic root of 81634771 is about 433.8021761184.

The spelling of 81634771 in words is "eighty-one million, six hundred thirty-four thousand, seven hundred seventy-one".