666021603 has 16 divisors (see below), whose sum is σ = 997920000. Its totient is φ = 392038944.

The previous prime is 666021599. The next prime is 666021613. The reversal of 666021603 is 306120666.

It is not a de Polignac number, because 666021603 - 2² = 666021599 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666021613) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 370353 + ... + 372146.

It is an arithmetic number, because the mean of its divisors is an integer number (62370000).

Almost surely, 2^666021603 is an apocalyptic number.

666021603 is a deficient number, since it is larger than the sum of its proper divisors (331898397).

666021603 is a wasteful number, since it uses less digits than its factorization.

666021603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 742538.

The product of its (nonzero) digits is 7776, while the sum is 30.

The square root of 666021603 is about 25807.3943473571. The cubic root of 666021603 is about 873.2986163028.

The spelling of 666021603 in words is "six hundred sixty-six million, twenty-one thousand, six hundred three".