129866123 has 4 divisors (see below), whose sum is σ = 132629280. Its totient is φ = 127102968.

The previous prime is 129866081. The next prime is 129866131. The reversal of 129866123 is 321668921.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 129866123 - 2¹⁸ = 129603979 is a prime.

It is a super-2 number, since 2×129866123² = 33730419806102258, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129866173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1381508 + ... + 1381601.

It is an arithmetic number, because the mean of its divisors is an integer number (33157320).

Almost surely, 2^129866123 is an apocalyptic number.

129866123 is a deficient number, since it is larger than the sum of its proper divisors (2763157).

129866123 is an equidigital number, since it uses as much as digits as its factorization.

129866123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2763156.

The product of its digits is 31104, while the sum is 38.

The square root of 129866123 is about 11395.8818438943. The cubic root of 129866123 is about 506.4057463595.

The spelling of 129866123 in words is "one hundred twenty-nine million, eight hundred sixty-six thousand, one hundred twenty-three".