666502643 has 4 divisors (see below), whose sum is σ = 666754848. Its totient is φ = 666250440.

The previous prime is 666502633. The next prime is 666502649. The reversal of 666502643 is 346205666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666502643 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666502597 and 666502606.

It is not an unprimeable number, because it can be changed into a prime (666502649) by changing a digit.

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, 122096 + ... + 127437.

It is an arithmetic number, because the mean of its divisors is an integer number (166688712).

Almost surely, 2^666502643 is an apocalyptic number.

666502643 is a deficient number, since it is larger than the sum of its proper divisors (252205).

666502643 is a wasteful number, since it uses less digits than its factorization.

666502643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252204.

The product of its (nonzero) digits is 155520, while the sum is 38.

The square root of 666502643 is about 25816.7124746742. The cubic root of 666502643 is about 873.5088149244.

The spelling of 666502643 in words is "six hundred sixty-six million, five hundred two thousand, six hundred forty-three".