81658387 has 2 divisors, whose sum is σ = 81658388. Its totient is φ = 81658386.

The previous prime is 81658351. The next prime is 81658391. The reversal of 81658387 is 78385618.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81658387 is a prime.

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 (81658397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40829193 + 40829194.

It is an arithmetic number, because the mean of its divisors is an integer number (40829194).

Almost surely, 2^81658387 is an apocalyptic number.

81658387 is a deficient number, since it is larger than the sum of its proper divisors (1).

81658387 is an equidigital number, since it uses as much as digits as its factorization.

81658387 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 322560, while the sum is 46.

The square root of 81658387 is about 9036.5030293803. The cubic root of 81658387 is about 433.8440034115.

The spelling of 81658387 in words is "eighty-one million, six hundred fifty-eight thousand, three hundred eighty-seven".