666541611 has 24 divisors (see below), whose sum is σ = 986126960. Its totient is φ = 433714176.

The previous prime is 666541607. The next prime is 666541663. The reversal of 666541611 is 116145666.

It is a happy number.

It is not a de Polignac number, because 666541611 - 2² = 666541607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666541111) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 58500 + ... + 68958.

Almost surely, 2^666541611 is an apocalyptic number.

666541611 is a deficient number, since it is larger than the sum of its proper divisors (319585349).

666541611 is a wasteful number, since it uses less digits than its factorization.

666541611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10635 (or 10632 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 666541611 is about 25817.4671685663. The cubic root of 666541611 is about 873.5258382268.

It can be divided in two parts, 66654 and 1611, that added together give a triangular number (68265 = T₃₆₉).

The spelling of 666541611 in words is "six hundred sixty-six million, five hundred forty-one thousand, six hundred eleven".