172821889 has 2 divisors, whose sum is σ = 172821890. Its totient is φ = 172821888.

The previous prime is 172821851. The next prime is 172821911. The reversal of 172821889 is 988128271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 169520400 + 3301489 = 13020^2 + 1817^2 .

It is a cyclic number.

It is not a de Polignac number, because 172821889 - 2⁹ = 172821377 is a prime.

It is not a weakly prime, because it can be changed into another prime (172821809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86410944 + 86410945.

It is an arithmetic number, because the mean of its divisors is an integer number (86410945).

Almost surely, 2^172821889 is an apocalyptic number.

It is an amenable number.

172821889 is a deficient number, since it is larger than the sum of its proper divisors (1).

172821889 is an equidigital number, since it uses as much as digits as its factorization.

172821889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129024, while the sum is 46.

The square root of 172821889 is about 13146.1739300832. The cubic root of 172821889 is about 557.0141774984.

The spelling of 172821889 in words is "one hundred seventy-two million, eight hundred twenty-one thousand, eight hundred eighty-nine".