81849563 has 4 divisors (see below), whose sum is σ = 82273848. Its totient is φ = 81425280.

The previous prime is 81849553. The next prime is 81849569. The reversal of 81849563 is 36594818.

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

It is a cyclic number.

It is not a de Polignac number, because 81849563 - 2¹⁸ = 81587419 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81849569) 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, 211853 + ... + 212238.

It is an arithmetic number, because the mean of its divisors is an integer number (20568462).

Almost surely, 2^81849563 is an apocalyptic number.

81849563 is a deficient number, since it is larger than the sum of its proper divisors (424285).

81849563 is a wasteful number, since it uses less digits than its factorization.

81849563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424284.

The product of its digits is 207360, while the sum is 44.

The square root of 81849563 is about 9047.0748311264. The cubic root of 81849563 is about 434.1823067684.

The spelling of 81849563 in words is "eighty-one million, eight hundred forty-nine thousand, five hundred sixty-three".