189216191581 has 2 divisors, whose sum is σ = 189216191582. Its totient is φ = 189216191580.

The previous prime is 189216191561. The next prime is 189216191609. The reversal of 189216191581 is 185191612981.

189216191581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 142834108356 + 46382083225 = 377934^2 + 215365^2 .

It is a cyclic number.

It is not a de Polignac number, because 189216191581 - 2³³ = 180626256989 is a prime.

It is a super-2 number, since 2×189216191581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (189216191561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94608095790 + 94608095791.

It is an arithmetic number, because the mean of its divisors is an integer number (94608095791).

Almost surely, 2^189216191581 is an apocalyptic number.

It is an amenable number.

189216191581 is a deficient number, since it is larger than the sum of its proper divisors (1).

189216191581 is an equidigital number, since it uses as much as digits as its factorization.

189216191581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 52.

The spelling of 189216191581 in words is "one hundred eighty-nine billion, two hundred sixteen million, one hundred ninety-one thousand, five hundred eighty-one".