666940558 has 4 divisors (see below), whose sum is σ = 1000410840. Its totient is φ = 333470278.

The previous prime is 666940529. The next prime is 666940567. The reversal of 666940558 is 855049666.

It is a happy number.

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

It is a super-3 number, since 3×666940558³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166735138 + ... + 166735141.

It is an arithmetic number, because the mean of its divisors is an integer number (250102710).

Almost surely, 2^666940558 is an apocalyptic number.

666940558 is a deficient number, since it is larger than the sum of its proper divisors (333470282).

666940558 is a wasteful number, since it uses less digits than its factorization.

666940558 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333470281.

The product of its (nonzero) digits is 1555200, while the sum is 49.

The square root of 666940558 is about 25825.1923129335. The cubic root of 666940558 is about 873.7000814159.

The spelling of 666940558 in words is "six hundred sixty-six million, nine hundred forty thousand, five hundred fifty-eight".