129021823 has 8 divisors (see below), whose sum is σ = 156127392. Its totient is φ = 104084736.

The previous prime is 129021821. The next prime is 129021847. The reversal of 129021823 is 328120921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 129021823 - 2¹ = 129021821 is a prime.

It is a super-3 number, since 3×129021823³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 129021791 and 129021800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129021821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 541990 + ... + 542227.

It is an arithmetic number, because the mean of its divisors is an integer number (19515924).

Almost surely, 2^129021823 is an apocalyptic number.

129021823 is a deficient number, since it is larger than the sum of its proper divisors (27105569).

129021823 is a wasteful number, since it uses less digits than its factorization.

129021823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1084241.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 129021823 is about 11358.7773549797. Note that the first 3 decimals coincide. The cubic root of 129021823 is about 505.3059258002.

The spelling of 129021823 in words is "one hundred twenty-nine million, twenty-one thousand, eight hundred twenty-three".