81458987 has 2 divisors, whose sum is σ = 81458988. Its totient is φ = 81458986.

The previous prime is 81458983. The next prime is 81458989. The reversal of 81458987 is 78985418.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81458987 - 2² = 81458983 is a prime.

Together with 81458989, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (81458983) 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, 40729493 + 40729494.

It is an arithmetic number, because the mean of its divisors is an integer number (40729494).

Almost surely, 2^81458987 is an apocalyptic number.

81458987 is a deficient number, since it is larger than the sum of its proper divisors (1).

81458987 is an equidigital number, since it uses as much as digits as its factorization.

81458987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 645120, while the sum is 50.

The square root of 81458987 is about 9025.4632568085. The cubic root of 81458987 is about 433.4905838890.

The spelling of 81458987 in words is "eighty-one million, four hundred fifty-eight thousand, nine hundred eighty-seven".