81673556 has 12 divisors (see below), whose sum is σ = 143183040. Its totient is φ = 40764120.

The previous prime is 81673513. The next prime is 81673567. The reversal of 81673556 is 65537618.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15596 + ... + 20163.

It is an arithmetic number, because the mean of its divisors is an integer number (11931920).

Almost surely, 2^81673556 is an apocalyptic number.

It is an amenable number.

81673556 is a deficient number, since it is larger than the sum of its proper divisors (61509484).

81673556 is a wasteful number, since it uses less digits than its factorization.

81673556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36334 (or 36332 counting only the distinct ones).

The product of its digits is 151200, while the sum is 41.

The square root of 81673556 is about 9037.3423084444. The cubic root of 81673556 is about 433.8708656134.

The spelling of 81673556 in words is "eighty-one million, six hundred seventy-three thousand, five hundred fifty-six".