666889405 has 16 divisors (see below), whose sum is σ = 984945024. Its totient is φ = 422118720.

The previous prime is 666889361. The next prime is 666889409. The reversal of 666889405 is 504988666.

It is not a de Polignac number, because 666889405 - 2¹¹ = 666887357 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666889409) 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, 732391 + ... + 733300.

It is an arithmetic number, because the mean of its divisors is an integer number (61559064).

Almost surely, 2^666889405 is an apocalyptic number.

666889405 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

666889405 is a deficient number, since it is larger than the sum of its proper divisors (318055619).

666889405 is a wasteful number, since it uses less digits than its factorization.

666889405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1465716.

The product of its (nonzero) digits is 2488320, while the sum is 52.

The square root of 666889405 is about 25824.2019237769. The cubic root of 666889405 is about 873.6777438316.

The spelling of 666889405 in words is "six hundred sixty-six million, eight hundred eighty-nine thousand, four hundred five".