81634849 has 4 divisors (see below), whose sum is σ = 85931440. Its totient is φ = 77338260.

The previous prime is 81634831. The next prime is 81634859. The reversal of 81634849 is 94843618.

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.

It is a cyclic number.

It is not a de Polignac number, because 81634849 - 2¹¹ = 81632801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81634829) 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, 2148267 + ... + 2148304.

It is an arithmetic number, because the mean of its divisors is an integer number (21482860).

Almost surely, 2^81634849 is an apocalyptic number.

It is an amenable number.

81634849 is a deficient number, since it is larger than the sum of its proper divisors (4296591).

81634849 is a wasteful number, since it uses less digits than its factorization.

81634849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4296590.

The product of its digits is 165888, while the sum is 43.

The square root of 81634849 is about 9035.2005511776. The cubic root of 81634849 is about 433.8023142808.

The spelling of 81634849 in words is "eighty-one million, six hundred thirty-four thousand, eight hundred forty-nine".