668543986 has 32 divisors (see below), whose sum is σ = 1115674560. Its totient is φ = 297888000.

The previous prime is 668543983. The next prime is 668543987. The reversal of 668543986 is 689345866.

It is a happy number.

It is a super-2 number, since 2×668543986² = 893902122433536392, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (668543983) 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, 779670 + ... + 780526.

It is an arithmetic number, because the mean of its divisors is an integer number (34864830).

Almost surely, 2^668543986 is an apocalyptic number.

668543986 is a deficient number, since it is larger than the sum of its proper divisors (447130574).

668543986 is a wasteful number, since it uses less digits than its factorization.

668543986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530.

The product of its digits is 7464960, while the sum is 55.

The square root of 668543986 is about 25856.2175501368. The cubic root of 668543986 is about 874.3996909900.

The spelling of 668543986 in words is "six hundred sixty-eight million, five hundred forty-three thousand, nine hundred eighty-six".