81593851 has 2 divisors, whose sum is σ = 81593852. Its totient is φ = 81593850.

The previous prime is 81593821. The next prime is 81593861. The reversal of 81593851 is 15839518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81593851 - 2¹¹ = 81591803 is a prime.

It is not a weakly prime, because it can be changed into another prime (81593801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40796925 + 40796926.

It is an arithmetic number, because the mean of its divisors is an integer number (40796926).

Almost surely, 2^81593851 is an apocalyptic number.

81593851 is a deficient number, since it is larger than the sum of its proper divisors (1).

81593851 is an equidigital number, since it uses as much as digits as its factorization.

81593851 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 40.

The square root of 81593851 is about 9032.9314732262. The cubic root of 81593851 is about 433.7296818793.

The spelling of 81593851 in words is "eighty-one million, five hundred ninety-three thousand, eight hundred fifty-one".