666503201 has 16 divisors (see below), whose sum is σ = 848601600. Its totient is φ = 509156928.

The previous prime is 666503191. The next prime is 666503221. The reversal of 666503201 is 102305666.

It is not a de Polignac number, because 666503201 - 2¹⁴ = 666486817 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (666503221) 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, 123641 + ... + 128918.

It is an arithmetic number, because the mean of its divisors is an integer number (53037600).

Almost surely, 2^666503201 is an apocalyptic number.

It is an amenable number.

666503201 is a deficient number, since it is larger than the sum of its proper divisors (182098399).

666503201 is a wasteful number, since it uses less digits than its factorization.

666503201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252608.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 666503201 is about 25816.7232816250. The cubic root of 666503201 is about 873.5090586932.

Adding to 666503201 its reverse (102305666), we get a palindrome (768808867).

The spelling of 666503201 in words is "six hundred sixty-six million, five hundred three thousand, two hundred one".