81673805 has 8 divisors (see below), whose sum is σ = 102269952. Its totient is φ = 62498128.

The previous prime is 81673793. The next prime is 81673807. The reversal of 81673805 is 50837618.

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

It is a cyclic number.

It is not a de Polignac number, because 81673805 - 2⁶ = 81673741 is a prime.

It is a super-2 number, since 2×81673805² = 13341220846356050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81673807) 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, 354989 + ... + 355218.

It is an arithmetic number, because the mean of its divisors is an integer number (12783744).

Almost surely, 2^81673805 is an apocalyptic number.

It is an amenable number.

81673805 is a deficient number, since it is larger than the sum of its proper divisors (20596147).

81673805 is a wasteful number, since it uses less digits than its factorization.

81673805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 710235.

The product of its (nonzero) digits is 40320, while the sum is 38.

The square root of 81673805 is about 9037.3560846079. The cubic root of 81673805 is about 433.8713065302.

The spelling of 81673805 in words is "eighty-one million, six hundred seventy-three thousand, eight hundred five".