81673658 has 16 divisors (see below), whose sum is σ = 133812000. Its totient is φ = 37078800.

The previous prime is 81673651. The next prime is 81673673. The reversal of 81673658 is 85637618.

It is a super-2 number, since 2×81673658² = 13341172822201928, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81673651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21593 + ... + 25091.

It is an arithmetic number, because the mean of its divisors is an integer number (8363250).

Almost surely, 2^81673658 is an apocalyptic number.

81673658 is a deficient number, since it is larger than the sum of its proper divisors (52138342).

81673658 is a wasteful number, since it uses less digits than its factorization.

81673658 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4573.

The product of its digits is 241920, while the sum is 44.

The square root of 81673658 is about 9037.3479516947. The cubic root of 81673658 is about 433.8710462300.

The spelling of 81673658 in words is "eighty-one million, six hundred seventy-three thousand, six hundred fifty-eight".