666355638 has 32 divisors (see below), whose sum is σ = 1451368800. Its totient is φ = 202726656.

The previous prime is 666355637. The next prime is 666355673. The reversal of 666355638 is 836553666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666355637) 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, 41053 + ... + 54936.

It is an arithmetic number, because the mean of its divisors is an integer number (45355275).

Almost surely, 2^666355638 is an apocalyptic number.

666355638 is an abundant number, since it is smaller than the sum of its proper divisors (785013162).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

666355638 is a wasteful number, since it uses less digits than its factorization.

666355638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96096.

The product of its digits is 2332800, while the sum is 48.

The square root of 666355638 is about 25813.8652278189. The cubic root of 666355638 is about 873.4445893199. Note that the first 3 decimals are identical.

The spelling of 666355638 in words is "six hundred sixty-six million, three hundred fifty-five thousand, six hundred thirty-eight".