129742181 has 8 divisors (see below), whose sum is σ = 139627224. Its totient is φ = 120107520.

The previous prime is 129742177. The next prime is 129742211. The reversal of 129742181 is 181247921.

It can be written as a sum of positive squares in 4 ways, for example, as 919681 + 128822500 = 959^2 + 11350^2 .

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 129742181 - 2² = 129742177 is a prime.

It is a super-2 number, since 2×129742181² = 33666067061273522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129742111) 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, 61520 + ... + 63593.

It is an arithmetic number, because the mean of its divisors is an integer number (17453403).

Almost surely, 2^129742181 is an apocalyptic number.

It is an amenable number.

129742181 is a deficient number, since it is larger than the sum of its proper divisors (9885043).

129742181 is a wasteful number, since it uses less digits than its factorization.

129742181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125191.

The product of its digits is 8064, while the sum is 35.

The square root of 129742181 is about 11390.4425287168. The cubic root of 129742181 is about 506.2445934290.

The spelling of 129742181 in words is "one hundred twenty-nine million, seven hundred forty-two thousand, one hundred eighty-one".