1666130621 has 8 divisors (see below), whose sum is σ = 1672962360. Its totient is φ = 1659313152.

The previous prime is 1666130581. The next prime is 1666130623. The reversal of 1666130621 is 1260316661.

It can be written as a sum of positive squares in 4 ways, for example, as 138415225 + 1527715396 = 11765^2 + 39086^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666130621 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 (1666130623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 272231 + ... + 278283.

It is an arithmetic number, because the mean of its divisors is an integer number (209120295).

Almost surely, 2^1666130621 is an apocalyptic number.

It is an amenable number.

1666130621 is a deficient number, since it is larger than the sum of its proper divisors (6831739).

1666130621 is an equidigital number, since it uses as much as digits as its factorization.

1666130621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7135.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 1666130621 is about 40818.2633266042. The cubic root of 1666130621 is about 1185.5039773840.

The spelling of 1666130621 in words is "one billion, six hundred sixty-six million, one hundred thirty thousand, six hundred twenty-one".