666256445 has 4 divisors (see below), whose sum is σ = 799507740. Its totient is φ = 533005152.

The previous prime is 666256439. The next prime is 666256453. The reversal of 666256445 is 544652666.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 211586116 + 454670329 = 14546^2 + 21323^2 .

It is a cyclic number.

It is not a de Polignac number, because 666256445 - 2¹⁶ = 666190909 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 666256396 and 666256405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66625640 + ... + 66625649.

It is an arithmetic number, because the mean of its divisors is an integer number (199876935).

Almost surely, 2^666256445 is an apocalyptic number.

It is an amenable number.

666256445 is a deficient number, since it is larger than the sum of its proper divisors (133251295).

666256445 is a wasteful number, since it uses less digits than its factorization.

666256445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133251294.

The product of its digits is 1036800, while the sum is 44.

The square root of 666256445 is about 25811.9438438875. The cubic root of 666256445 is about 873.4012471547.

The spelling of 666256445 in words is "six hundred sixty-six million, two hundred fifty-six thousand, four hundred forty-five".