128729669 has 2 divisors, whose sum is σ = 128729670. Its totient is φ = 128729668.

The previous prime is 128729641. The next prime is 128729677. The reversal of 128729669 is 966927821.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122921569 + 5808100 = 11087^2 + 2410^2 .

It is a cyclic number.

It is not a de Polignac number, because 128729669 - 2¹² = 128725573 is a prime.

It is a super-2 number, since 2×128729669² = 33142655361699122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128729609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64364834 + 64364835.

It is an arithmetic number, because the mean of its divisors is an integer number (64364835).

Almost surely, 2^128729669 is an apocalyptic number.

It is an amenable number.

128729669 is a deficient number, since it is larger than the sum of its proper divisors (1).

128729669 is an equidigital number, since it uses as much as digits as its factorization.

128729669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 50.

The square root of 128729669 is about 11345.9097916386. The cubic root of 128729669 is about 504.9242365836.

The spelling of 128729669 in words is "one hundred twenty-eight million, seven hundred twenty-nine thousand, six hundred sixty-nine".