660166621 has 8 divisors (see below), whose sum is σ = 665532000. Its totient is φ = 654823248.

The previous prime is 660166597. The next prime is 660166651. The reversal of 660166621 is 126661066.

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 660166621 - 2¹¹ = 660164573 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 (660166651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57630 + ... + 68128.

It is an arithmetic number, because the mean of its divisors is an integer number (83191500).

Almost surely, 2^660166621 is an apocalyptic number.

It is an amenable number.

660166621 is a deficient number, since it is larger than the sum of its proper divisors (5365379).

660166621 is a wasteful number, since it uses less digits than its factorization.

660166621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11003.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 660166621 is about 25693.7078095008. The cubic root of 660166621 is about 870.7320306469.

It can be divided in two parts, 660 and 166621, that added together give a square (167281 = 409²).

The spelling of 660166621 in words is "six hundred sixty million, one hundred sixty-six thousand, six hundred twenty-one".