191728129 has 2 divisors, whose sum is σ = 191728130. Its totient is φ = 191728128.

The previous prime is 191728127. The next prime is 191728151. The reversal of 191728129 is 921827191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 120494529 + 71233600 = 10977^2 + 8440^2 .

It is a cyclic number.

It is not a de Polignac number, because 191728129 - 2¹ = 191728127 is a prime.

Together with 191728127, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 191728091 and 191728100.

It is not a weakly prime, because it can be changed into another prime (191728127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95864064 + 95864065.

It is an arithmetic number, because the mean of its divisors is an integer number (95864065).

Almost surely, 2^191728129 is an apocalyptic number.

It is an amenable number.

191728129 is a deficient number, since it is larger than the sum of its proper divisors (1).

191728129 is an equidigital number, since it uses as much as digits as its factorization.

191728129 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 40.

The square root of 191728129 is about 13846.5926855671. The cubic root of 191728129 is about 576.6274037813.

The spelling of 191728129 in words is "one hundred ninety-one million, seven hundred twenty-eight thousand, one hundred twenty-nine".