81057673 has 2 divisors, whose sum is σ = 81057674. Its totient is φ = 81057672.

The previous prime is 81057661. The next prime is 81057677. The reversal of 81057673 is 37675018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80784144 + 273529 = 8988^2 + 523^2 .

It is a cyclic number.

It is not a de Polignac number, because 81057673 - 2¹³ = 81049481 is a prime.

It is equal to p_4727638 and since 81057673 and 4727638 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81057677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40528836 + 40528837.

It is an arithmetic number, because the mean of its divisors is an integer number (40528837).

Almost surely, 2^81057673 is an apocalyptic number.

It is an amenable number.

81057673 is a deficient number, since it is larger than the sum of its proper divisors (1).

81057673 is an equidigital number, since it uses as much as digits as its factorization.

81057673 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 35280, while the sum is 37.

The square root of 81057673 is about 9003.2034854267. The cubic root of 81057673 is about 432.7775366796. Note that the first 3 decimals are identical.

The spelling of 81057673 in words is "eighty-one million, fifty-seven thousand, six hundred seventy-three".