81210849 has 4 divisors (see below), whose sum is σ = 108281136. Its totient is φ = 54140564.

The previous prime is 81210823. The next prime is 81210881. The reversal of 81210849 is 94801218.

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 81210849 - 2⁷ = 81210721 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81200849) 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, 13535139 + ... + 13535144.

It is an arithmetic number, because the mean of its divisors is an integer number (27070284).

Almost surely, 2^81210849 is an apocalyptic number.

It is an amenable number.

81210849 is a deficient number, since it is larger than the sum of its proper divisors (27070287).

81210849 is a wasteful number, since it uses less digits than its factorization.

81210849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27070286.

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 81210849 is about 9011.7062202449. The cubic root of 81210849 is about 433.0499740531.

The spelling of 81210849 in words is "eighty-one million, two hundred ten thousand, eight hundred forty-nine".