66621587 has 2 divisors, whose sum is σ = 66621588. Its totient is φ = 66621586.

The previous prime is 66621559. The next prime is 66621617. The reversal of 66621587 is 78512666.

66621587 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66621587 - 2¹⁰ = 66620563 is a prime.

It is not a weakly prime, because it can be changed into another prime (66621557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33310793 + 33310794.

It is an arithmetic number, because the mean of its divisors is an integer number (33310794).

Almost surely, 2^66621587 is an apocalyptic number.

66621587 is a deficient number, since it is larger than the sum of its proper divisors (1).

66621587 is an equidigital number, since it uses as much as digits as its factorization.

66621587 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 41.

The square root of 66621587 is about 8162.2047879234. The cubic root of 66621587 is about 405.3887178841.

The spelling of 66621587 in words is "sixty-six million, six hundred twenty-one thousand, five hundred eighty-seven".