66621685 has 16 divisors (see below), whose sum is σ = 89841024. Its totient is φ = 47057472.

The previous prime is 66621677. The next prime is 66621707. The reversal of 66621685 is 58612666.

It is a cyclic number.

It is not a de Polignac number, because 66621685 - 2³ = 66621677 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20787 + ... + 23776.

It is an arithmetic number, because the mean of its divisors is an integer number (5615064).

Almost surely, 2^66621685 is an apocalyptic number.

66621685 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

66621685 is a deficient number, since it is larger than the sum of its proper divisors (23219339).

66621685 is a wasteful number, since it uses less digits than its factorization.

66621685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44604.

The product of its digits is 103680, while the sum is 40.

The square root of 66621685 is about 8162.2107912011. The cubic root of 66621685 is about 405.3889166589.

The spelling of 66621685 in words is "sixty-six million, six hundred twenty-one thousand, six hundred eighty-five".