188818561 has 8 divisors (see below), whose sum is σ = 199213920. Its totient is φ = 178468992.

The previous prime is 188818549. The next prime is 188818603. The reversal of 188818561 is 165818881.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 188818561 - 2²⁵ = 155264129 is a prime.

It is a super-2 number, since 2×188818561² = 71304897956221442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (188858561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2800 + ... + 19633.

It is an arithmetic number, because the mean of its divisors is an integer number (24901740).

Almost surely, 2^188818561 is an apocalyptic number.

It is an amenable number.

188818561 is a deficient number, since it is larger than the sum of its proper divisors (10395359).

188818561 is a wasteful number, since it uses less digits than its factorization.

188818561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22895.

The product of its digits is 122880, while the sum is 46.

The square root of 188818561 is about 13741.1266277551. The cubic root of 188818561 is about 573.6956556543.

It can be divided in two parts, 1888 and 18561, that added together give a square (20449 = 143²).

The spelling of 188818561 in words is "one hundred eighty-eight million, eight hundred eighteen thousand, five hundred sixty-one".