81673807 has 2 divisors, whose sum is σ = 81673808. Its totient is φ = 81673806.

The previous prime is 81673793. The next prime is 81673843. The reversal of 81673807 is 70837618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81673807 - 2⁷ = 81673679 is a prime.

It is a super-2 number, since 2×81673807² = 13341221499746498, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81673807.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81670807) 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 as a sum of consecutive naturals, namely, 40836903 + 40836904.

It is an arithmetic number, because the mean of its divisors is an integer number (40836904).

Almost surely, 2^81673807 is an apocalyptic number.

81673807 is a deficient number, since it is larger than the sum of its proper divisors (1).

81673807 is an equidigital number, since it uses as much as digits as its factorization.

81673807 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56448, while the sum is 40.

The square root of 81673807 is about 9037.3561952598. The cubic root of 81673807 is about 433.8713100717.

The spelling of 81673807 in words is "eighty-one million, six hundred seventy-three thousand, eight hundred seven".