666663610 has 8 divisors (see below), whose sum is σ = 1199994516. Its totient is φ = 266665440.

The previous prime is 666663593. The next prime is 666663617. The reversal of 666663610 is 16366666.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 666620761 + 42849 = 25819^2 + 207^2 .

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

It is not an unprimeable number, because it can be changed into a prime (666663617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33333171 + ... + 33333190.

Almost surely, 2^666663610 is an apocalyptic number.

666663610 is a deficient number, since it is larger than the sum of its proper divisors (533330906).

666663610 is a wasteful number, since it uses less digits than its factorization.

666663610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66666368.

The product of its (nonzero) digits is 139968, while the sum is 40.

The square root of 666663610 is about 25819.8297825528. The cubic root of 666663610 is about 873.5791296121.

The spelling of 666663610 in words is "six hundred sixty-six million, six hundred sixty-three thousand, six hundred ten".