189742878 has 64 divisors (see below), whose sum is σ = 468787200. Its totient is φ = 56492640.

The previous prime is 189742877. The next prime is 189742907. The reversal of 189742878 is 878247981.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189742877) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17403 + ... + 26121.

It is an arithmetic number, because the mean of its divisors is an integer number (7324800).

Almost surely, 2^189742878 is an apocalyptic number.

189742878 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 189742878, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (234393600).

189742878 is an abundant number, since it is smaller than the sum of its proper divisors (279044322).

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

189742878 is a wasteful number, since it uses less digits than its factorization.

189742878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8774 (or 8768 counting only the distinct ones).

The product of its digits is 1806336, while the sum is 54.

The square root of 189742878 is about 13774.7187993077. The cubic root of 189742878 is about 574.6302631217.

The spelling of 189742878 in words is "one hundred eighty-nine million, seven hundred forty-two thousand, eight hundred seventy-eight".