189778557 has 4 divisors (see below), whose sum is σ = 253038080. Its totient is φ = 126519036.

The previous prime is 189778553. The next prime is 189778573. The reversal of 189778557 is 755877981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 189778557 - 2² = 189778553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 189778497 and 189778506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (189778553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31629757 + ... + 31629762.

It is an arithmetic number, because the mean of its divisors is an integer number (63259520).

Almost surely, 2^189778557 is an apocalyptic number.

It is an amenable number.

189778557 is a deficient number, since it is larger than the sum of its proper divisors (63259523).

189778557 is an equidigital number, since it uses as much as digits as its factorization.

189778557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63259522.

The product of its digits is 4939200, while the sum is 57.

The square root of 189778557 is about 13776.0138283903. The cubic root of 189778557 is about 574.6662784361. Note that the first 3 decimals are identical.

The spelling of 189778557 in words is "one hundred eighty-nine million, seven hundred seventy-eight thousand, five hundred fifty-seven".