81538658 has 8 divisors (see below), whose sum is σ = 122923200. Its totient is φ = 40564260.

The previous prime is 81538643. The next prime is 81538669. The reversal of 81538658 is 85683518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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, 102038 + ... + 102833.

It is an arithmetic number, because the mean of its divisors is an integer number (15365400).

Almost surely, 2^81538658 is an apocalyptic number.

81538658 is a deficient number, since it is larger than the sum of its proper divisors (41384542).

81538658 is a wasteful number, since it uses less digits than its factorization.

81538658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205072.

The product of its digits is 230400, while the sum is 44.

The square root of 81538658 is about 9029.8758573969. The cubic root of 81538658 is about 433.6318630618.

The spelling of 81538658 in words is "eighty-one million, five hundred thirty-eight thousand, six hundred fifty-eight".