81623587 has 2 divisors, whose sum is σ = 81623588. Its totient is φ = 81623586.

The previous prime is 81623569. The next prime is 81623593. The reversal of 81623587 is 78532618.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81623587 is a prime.

It is not a weakly prime, because it can be changed into another prime (81623557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40811793 + 40811794.

It is an arithmetic number, because the mean of its divisors is an integer number (40811794).

Almost surely, 2^81623587 is an apocalyptic number.

81623587 is a deficient number, since it is larger than the sum of its proper divisors (1).

81623587 is an equidigital number, since it uses as much as digits as its factorization.

81623587 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 40.

The square root of 81623587 is about 9034.5773005714. The cubic root of 81623587 is about 433.7823648499.

The spelling of 81623587 in words is "eighty-one million, six hundred twenty-three thousand, five hundred eighty-seven".