129823812 has 36 divisors (see below), whose sum is σ = 329137900. Its totient is φ = 43146432.

The previous prime is 129823739. The next prime is 129823831. The reversal of 129823812 is 218328921.

It can be written as a sum of positive squares in 2 ways, for example, as 95531076 + 34292736 = 9774^2 + 5856^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×129823812² = 33708444324422688, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7398 + ... + 17730.

Almost surely, 2^129823812 is an apocalyptic number.

129823812 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

129823812 is an abundant number, since it is smaller than the sum of its proper divisors (199314088).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

129823812 is a wasteful number, since it uses less digits than its factorization.

129823812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10692 (or 10687 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 129823812 is about 11394.0252764333. The cubic root of 129823812 is about 506.3507439195.

The spelling of 129823812 in words is "one hundred twenty-nine million, eight hundred twenty-three thousand, eight hundred twelve".