66621671 has 8 divisors (see below), whose sum is σ = 69145920. Its totient is φ = 64112608.

The previous prime is 66621661. The next prime is 66621677. The reversal of 66621671 is 17612666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66621671 - 2¹⁰ = 66620647 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66621677) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5570 + ... + 12816.

It is an arithmetic number, because the mean of its divisors is an integer number (8643240).

Almost surely, 2^66621671 is an apocalyptic number.

66621671 is a deficient number, since it is larger than the sum of its proper divisors (2524249).

66621671 is a wasteful number, since it uses less digits than its factorization.

66621671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7593.

The product of its digits is 18144, while the sum is 35.

The square root of 66621671 is about 8162.2099335903. The cubic root of 66621671 is about 405.3888882625.

The spelling of 66621671 in words is "sixty-six million, six hundred twenty-one thousand, six hundred seventy-one".