81612849 has 4 divisors (see below), whose sum is σ = 108817136. Its totient is φ = 54408564.

The previous prime is 81612841. The next prime is 81612851. The reversal of 81612849 is 94821618.

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 not a de Polignac number, because 81612849 - 2³ = 81612841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81612841) 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, 13602139 + ... + 13602144.

It is an arithmetic number, because the mean of its divisors is an integer number (27204284).

Almost surely, 2^81612849 is an apocalyptic number.

It is an amenable number.

81612849 is a deficient number, since it is larger than the sum of its proper divisors (27204287).

81612849 is a wasteful number, since it uses less digits than its factorization.

81612849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27204286.

The product of its digits is 27648, while the sum is 39.

The square root of 81612849 is about 9033.9830086181. The cubic root of 81612849 is about 433.7633419201.

The spelling of 81612849 in words is "eighty-one million, six hundred twelve thousand, eight hundred forty-nine".