189981820 has 36 divisors (see below), whose sum is σ = 464100840. Its totient is φ = 65136288.

The previous prime is 189981809. The next prime is 189981881. The reversal of 189981820 is 28189981.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 95950 + ... + 97909.

It is an arithmetic number, because the mean of its divisors is an integer number (12891690).

Almost surely, 2^189981820 is an apocalyptic number.

189981820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

189981820 is an abundant number, since it is smaller than the sum of its proper divisors (274119020).

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

189981820 is a wasteful number, since it uses less digits than its factorization.

189981820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193882 (or 193873 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 46.

The square root of 189981820 is about 13783.3892784032. The cubic root of 189981820 is about 574.8713713537.

The spelling of 189981820 in words is "one hundred eighty-nine million, nine hundred eighty-one thousand, eight hundred twenty".