81804538 has 16 divisors (see below), whose sum is σ = 131286240. Its totient is φ = 38113200.

The previous prime is 81804517. The next prime is 81804539. The reversal of 81804538 is 83540818.

It is a junction number, because it is equal to n+sod(n) for n = 81804497 and 81804506.

It is not an unprimeable number, because it can be changed into a prime (81804539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15328 + ... + 19963.

It is an arithmetic number, because the mean of its divisors is an integer number (8205390).

Almost surely, 2^81804538 is an apocalyptic number.

81804538 is a deficient number, since it is larger than the sum of its proper divisors (49481702).

81804538 is a wasteful number, since it uses less digits than its factorization.

81804538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35373.

The product of its (nonzero) digits is 30720, while the sum is 37.

The square root of 81804538 is about 9044.5861154616. The cubic root of 81804538 is about 434.1026783894.

The spelling of 81804538 in words is "eighty-one million, eight hundred four thousand, five hundred thirty-eight".