666721732201 has 8 divisors (see below), whose sum is σ = 761972837184. Its totient is φ = 571471913040.

The previous prime is 666721732199. The next prime is 666721732207. The reversal of 666721732201 is 102237127666.

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

It is not a de Polignac number, because 666721732201 - 2¹ = 666721732199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666721732207) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1415046 + ... + 1826416.

It is an arithmetic number, because the mean of its divisors is an integer number (95246604648).

Almost surely, 2^666721732201 is an apocalyptic number.

It is an amenable number.

666721732201 is a deficient number, since it is larger than the sum of its proper divisors (95251104983).

666721732201 is a wasteful number, since it uses less digits than its factorization.

666721732201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642911.

The product of its (nonzero) digits is 254016, while the sum is 43.

Adding to 666721732201 its reverse (102237127666), we get a palindrome (768958859867).

The spelling of 666721732201 in words is "six hundred sixty-six billion, seven hundred twenty-one million, seven hundred thirty-two thousand, two hundred one".