666172735450 has 12 divisors (see below), whose sum is σ = 1239081288030. Its totient is φ = 266469094160.

The previous prime is 666172735421. The next prime is 666172735451. The reversal of 666172735450 is 54537271666.

It can be written as a sum of positive squares in 3 ways, for example, as 423843967089 + 242328768361 = 651033^2 + 492269^2 .

It is a super-2 number, since 2×666172735450² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (666172735451) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6661727305 + ... + 6661727404.

Almost surely, 2^666172735450 is an apocalyptic number.

666172735450 is a deficient number, since it is larger than the sum of its proper divisors (572908552580).

666172735450 is a wasteful number, since it uses less digits than its factorization.

666172735450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13323454721 (or 13323454716 counting only the distinct ones).

The product of its (nonzero) digits is 6350400, while the sum is 52.

The spelling of 666172735450 in words is "six hundred sixty-six billion, one hundred seventy-two million, seven hundred thirty-five thousand, four hundred fifty".