66159621 has 24 divisors (see below), whose sum is σ = 105225120. Its totient is φ = 39722400.

The previous prime is 66159607. The next prime is 66159623. The reversal of 66159621 is 12695166.

66159621 is a `hidden beast` number, since 6 + 61 + 596 + 2 + 1 = 666.

It is not a de Polignac number, because 66159621 - 2⁶ = 66159557 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66159623) 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 in 23 ways as a sum of consecutive naturals, for example, 7726 + ... + 13856.

It is an arithmetic number, because the mean of its divisors is an integer number (4384380).

Almost surely, 2^66159621 is an apocalyptic number.

It is an amenable number.

66159621 is a deficient number, since it is larger than the sum of its proper divisors (39065499).

66159621 is a wasteful number, since it uses less digits than its factorization.

66159621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6257 (or 6254 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 66159621 is about 8133.8564654166. The cubic root of 66159621 is about 404.4495310721.

The spelling of 66159621 in words is "sixty-six million, one hundred fifty-nine thousand, six hundred twenty-one".