129869 has 4 divisors (see below), whose sum is σ = 132060. Its totient is φ = 127680.

The previous prime is 129853. The next prime is 129887. The reversal of 129869 is 968921.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15625 + 114244 = 125^2 + 338^2 .

It is a cyclic number.

It is not a de Polignac number, because 129869 - 2⁴ = 129853 is a prime.

It is a super-2 number, since 2×129869² = 33731914322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129169) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1004 + ... + 1125.

It is an arithmetic number, because the mean of its divisors is an integer number (33015).

2¹²⁹⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

129869 is a deficient number, since it is larger than the sum of its proper divisors (2191).

129869 is an equidigital number, since it uses as much as digits as its factorization.

129869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2190.

The product of its digits is 7776, while the sum is 35.

The square root of 129869 is about 360.3734174436. The cubic root of 129869 is about 50.6409485899.

It can be divided in two parts, 129 and 869, that multiplied together give a triangular number (112101 = T₄₇₃).

The spelling of 129869 in words is "one hundred twenty-nine thousand, eight hundred sixty-nine".