666356389 has 4 divisors (see below), whose sum is σ = 674791360. Its totient is φ = 657921420.

The previous prime is 666356381. The next prime is 666356393. The reversal of 666356389 is 983653666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 666356389 - 2³ = 666356381 is a prime.

It is a super-2 number, since 2×666356389² = 888061674322238642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666356381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4217367 + ... + 4217524.

It is an arithmetic number, because the mean of its divisors is an integer number (168697840).

Almost surely, 2^666356389 is an apocalyptic number.

It is an amenable number.

666356389 is a deficient number, since it is larger than the sum of its proper divisors (8434971).

666356389 is an equidigital number, since it uses as much as digits as its factorization.

666356389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8434970.

The product of its digits is 4199040, while the sum is 52.

The square root of 666356389 is about 25813.8797742610. The cubic root of 666356389 is about 873.4449174514. Note that the first 3 decimals are identical.

The spelling of 666356389 in words is "six hundred sixty-six million, three hundred fifty-six thousand, three hundred eighty-nine".