189939780 has 72 divisors (see below), whose sum is σ = 577718232. Its totient is φ = 50512896.

The previous prime is 189939721. The next prime is 189939781. The reversal of 189939780 is 87939981.

It can be written as a sum of positive squares in 4 ways, for example, as 24920064 + 165019716 = 4992^2 + 12846^2 .

It is not an unprimeable number, because it can be changed into a prime (189939781) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 76722 + ... + 79158.

Almost surely, 2^189939780 is an apocalyptic number.

189939780 is a gapful number since it is divisible by the number (10) 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 189939780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (288859116).

189939780 is an abundant number, since it is smaller than the sum of its proper divisors (387778452).

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

189939780 is a wasteful number, since it uses less digits than its factorization.

189939780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2885 (or 2880 counting only the distinct ones).

The product of its (nonzero) digits is 979776, while the sum is 54.

The square root of 189939780 is about 13781.8641699880. The cubic root of 189939780 is about 574.8289648832.

The spelling of 189939780 in words is "one hundred eighty-nine million, nine hundred thirty-nine thousand, seven hundred eighty".