81624619 has 2 divisors, whose sum is σ = 81624620. Its totient is φ = 81624618.

The previous prime is 81624601. The next prime is 81624623. The reversal of 81624619 is 91642618.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81624619 - 2¹¹ = 81622571 is a prime.

It is a super-2 number, since 2×81624619² = 13325156853790322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81624679) 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, 40812309 + 40812310.

It is an arithmetic number, because the mean of its divisors is an integer number (40812310).

Almost surely, 2^81624619 is an apocalyptic number.

81624619 is a deficient number, since it is larger than the sum of its proper divisors (1).

81624619 is an equidigital number, since it uses as much as digits as its factorization.

81624619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 37.

The square root of 81624619 is about 9034.6344142970. The cubic root of 81624619 is about 433.7841930041.

The spelling of 81624619 in words is "eighty-one million, six hundred twenty-four thousand, six hundred nineteen".