81247423 has 2 divisors, whose sum is σ = 81247424. Its totient is φ = 81247422.

The previous prime is 81247409. The next prime is 81247427. The reversal of 81247423 is 32474218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81247423 - 2⁹ = 81246911 is a prime.

It is a super-2 number, since 2×81247423² = 13202287488281858, which contains 22 as substring.

It is equal to p_4738135 and since 81247423 and 4738135 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81247427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40623711 + 40623712.

It is an arithmetic number, because the mean of its divisors is an integer number (40623712).

Almost surely, 2^81247423 is an apocalyptic number.

81247423 is a deficient number, since it is larger than the sum of its proper divisors (1).

81247423 is an equidigital number, since it uses as much as digits as its factorization.

81247423 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10752, while the sum is 31.

The square root of 81247423 is about 9013.7352412859. The cubic root of 81247423 is about 433.1149735489.

The spelling of 81247423 in words is "eighty-one million, two hundred forty-seven thousand, four hundred twenty-three".