81538927 has 2 divisors, whose sum is σ = 81538928. Its totient is φ = 81538926.

The previous prime is 81538921. The next prime is 81538931. The reversal of 81538927 is 72983518.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81538927 is a prime.

It is a super-2 number, since 2×81538927² = 13297193232622658, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81538921) 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, 40769463 + 40769464.

It is an arithmetic number, because the mean of its divisors is an integer number (40769464).

Almost surely, 2^81538927 is an apocalyptic number.

81538927 is a deficient number, since it is larger than the sum of its proper divisors (1).

81538927 is an equidigital number, since it uses as much as digits as its factorization.

81538927 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 43.

The square root of 81538927 is about 9029.8907523845. The cubic root of 81538927 is about 433.6323399188.

The spelling of 81538927 in words is "eighty-one million, five hundred thirty-eight thousand, nine hundred twenty-seven".