186721668 has 72 divisors (see below), whose sum is σ = 542662848. Its totient is φ = 53028288.

The previous prime is 186721657. The next prime is 186721673. The reversal of 186721668 is 866127681.

It is a happy number.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41455 + ... + 45737.

It is an arithmetic number, because the mean of its divisors is an integer number (7536984).

Almost surely, 2^186721668 is an apocalyptic number.

186721668 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 186721668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (271331424).

186721668 is an abundant number, since it is smaller than the sum of its proper divisors (355941180).

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

186721668 is a wasteful number, since it uses less digits than its factorization.

186721668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4473 (or 4468 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 186721668 is about 13664.6137157257. The cubic root of 186721668 is about 571.5640515788.

The spelling of 186721668 in words is "one hundred eighty-six million, seven hundred twenty-one thousand, six hundred sixty-eight".