81849073 has 4 divisors (see below), whose sum is σ = 81869940. Its totient is φ = 81828208.

The previous prime is 81849041. The next prime is 81849077. The reversal of 81849073 is 37094818.

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

It can be written as a sum of positive squares in 2 ways, for example, as 78269409 + 3579664 = 8847^2 + 1892^2 .

It is a cyclic number.

It is not a de Polignac number, because 81849073 - 2⁵ = 81849041 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81849077) 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, 2578 + ... + 13051.

It is an arithmetic number, because the mean of its divisors is an integer number (20467485).

Almost surely, 2^81849073 is an apocalyptic number.

It is an amenable number.

81849073 is a deficient number, since it is larger than the sum of its proper divisors (20867).

81849073 is a wasteful number, since it uses less digits than its factorization.

81849073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20866.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 81849073 is about 9047.0477505096. The cubic root of 81849073 is about 434.1814403424.

The spelling of 81849073 in words is "eighty-one million, eight hundred forty-nine thousand, seventy-three".