129681 has 10 divisors (see below), whose sum is σ = 193842. Its totient is φ = 86400.

The previous prime is 129671. The next prime is 129707. The reversal of 129681 is 186921.

It can be written as a sum of positive squares in only one way, i.e., 129600 + 81 = 360^2 + 9^2 .

It is not a de Polignac number, because 129681 - 2⁷ = 129553 is a prime.

It is a super-2 number, since 2×129681² = 33634323522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (129631) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 720 + ... + 881.

2¹²⁹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

129681 is a deficient number, since it is larger than the sum of its proper divisors (64161).

129681 is an equidigital number, since it uses as much as digits as its factorization.

129681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1613 (or 1604 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 129681 is about 360.1124824274. The cubic root of 129681 is about 50.6165006307.

It can be divided in two parts, 1296 and 81, that multiplied together give a 4-th power (104976 = 18⁴).

The spelling of 129681 in words is "one hundred twenty-nine thousand, six hundred eighty-one".