661343666 has 8 divisors (see below), whose sum is σ = 1026223020. Its totient is φ = 319269328.

The previous prime is 661343651. The next prime is 661343689. The reversal of 661343666 is 666343166.

It can be written as a sum of positive squares in 2 ways, for example, as 623950441 + 37393225 = 24979^2 + 6115^2 .

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

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 5701181 + ... + 5701296.

Almost surely, 2^661343666 is an apocalyptic number.

661343666 is a deficient number, since it is larger than the sum of its proper divisors (364879354).

661343666 is a wasteful number, since it uses less digits than its factorization.

661343666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11402508.

The product of its digits is 279936, while the sum is 41.

The square root of 661343666 is about 25716.6029249588. The cubic root of 661343666 is about 871.2492143613.

The spelling of 661343666 in words is "six hundred sixty-one million, three hundred forty-three thousand, six hundred sixty-six".