66998587 has 2 divisors, whose sum is σ = 66998588. Its totient is φ = 66998586.

The previous prime is 66998567. The next prime is 66998611. The reversal of 66998587 is 78589966.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66998587 - 2²³ = 58609979 is a prime.

It is not a weakly prime, because it can be changed into another prime (66998567) 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, 33499293 + 33499294.

It is an arithmetic number, because the mean of its divisors is an integer number (33499294).

Almost surely, 2^66998587 is an apocalyptic number.

66998587 is a deficient number, since it is larger than the sum of its proper divisors (1).

66998587 is an equidigital number, since it uses as much as digits as its factorization.

66998587 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6531840, while the sum is 58.

The square root of 66998587 is about 8185.2664587049. The cubic root of 66998587 is about 406.1519548168.

The spelling of 66998587 in words is "sixty-six million, nine hundred ninety-eight thousand, five hundred eighty-seven".