81804061 has 4 divisors (see below), whose sum is σ = 83799324. Its totient is φ = 79808800.

The previous prime is 81804059. The next prime is 81804113. The reversal of 81804061 is 16040818.

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 8444836 + 73359225 = 2906^2 + 8565^2 .

It is a cyclic number.

It is not a de Polignac number, because 81804061 - 2¹ = 81804059 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81804011) 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, 997570 + ... + 997651.

It is an arithmetic number, because the mean of its divisors is an integer number (20949831).

Almost surely, 2^81804061 is an apocalyptic number.

It is an amenable number.

81804061 is a deficient number, since it is larger than the sum of its proper divisors (1995263).

81804061 is a wasteful number, since it uses less digits than its factorization.

81804061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1995262.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 81804061 is about 9044.5597460573. The cubic root of 81804061 is about 434.1018346408.

Adding to 81804061 its reverse (16040818), we get a palindrome (97844879).

The spelling of 81804061 in words is "eighty-one million, eight hundred four thousand, sixty-one".