188645561 has 4 divisors (see below), whose sum is σ = 203156772. Its totient is φ = 174134352.

The previous prime is 188645521. The next prime is 188645579. The reversal of 188645561 is 165546881.

188645561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12924025 + 175721536 = 3595^2 + 13256^2 .

It is a cyclic number.

It is not a de Polignac number, because 188645561 - 2²⁶ = 121536697 is a prime.

It is not an unprimeable number, because it can be changed into a prime (188645521) 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, 7255586 + ... + 7255611.

It is an arithmetic number, because the mean of its divisors is an integer number (50789193).

Almost surely, 2^188645561 is an apocalyptic number.

It is an amenable number.

188645561 is a deficient number, since it is larger than the sum of its proper divisors (14511211).

188645561 is a wasteful number, since it uses less digits than its factorization.

188645561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14511210.

The product of its digits is 230400, while the sum is 44.

The square root of 188645561 is about 13734.8302137303. The cubic root of 188645561 is about 573.5203909719.

The spelling of 188645561 in words is "one hundred eighty-eight million, six hundred forty-five thousand, five hundred sixty-one".