1666385511 has 8 divisors (see below), whose sum is σ = 2539254144. Its totient is φ = 952220280.

The previous prime is 1666385507. The next prime is 1666385521. The reversal of 1666385511 is 1155836661.

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

It is not a de Polignac number, because 1666385511 - 2² = 1666385507 is a prime.

It is a super-2 number, since 2×1666385511² = 5553681342541462242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666385521) 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, 39675825 + ... + 39675866.

It is an arithmetic number, because the mean of its divisors is an integer number (317406768).

Almost surely, 2^1666385511 is an apocalyptic number.

1666385511 is a deficient number, since it is larger than the sum of its proper divisors (872868633).

1666385511 is an equidigital number, since it uses as much as digits as its factorization.

1666385511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79351701.

The product of its digits is 129600, while the sum is 42.

The square root of 1666385511 is about 40821.3854615445. The cubic root of 1666385511 is about 1185.5644283669.

The spelling of 1666385511 in words is "one billion, six hundred sixty-six million, three hundred eighty-five thousand, five hundred eleven".