1666775261 has 8 divisors (see below), whose sum is σ = 1727109120. Its totient is φ = 1606632048.

The previous prime is 1666775249. The next prime is 1666775303. The reversal of 1666775261 is 1625776661.

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-1666775261 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 (1666775221) 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, 29741 + ... + 64946.

It is an arithmetic number, because the mean of its divisors is an integer number (215888640).

Almost surely, 2^1666775261 is an apocalyptic number.

It is an amenable number.

1666775261 is a deficient number, since it is larger than the sum of its proper divisors (60333859).

1666775261 is an equidigital number, since it uses as much as digits as its factorization.

1666775261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95323.

The product of its digits is 635040, while the sum is 47.

The square root of 1666775261 is about 40826.1590282505. The cubic root of 1666775261 is about 1185.6568515012.

The spelling of 1666775261 in words is "one billion, six hundred sixty-six million, seven hundred seventy-five thousand, two hundred sixty-one".