129225510921 has 16 divisors (see below), whose sum is σ = 186159009344. Its totient is φ = 79264350144.

The previous prime is 129225510917. The next prime is 129225511013. The reversal of 129225510921 is 129015522921.

It is not a de Polignac number, because 129225510921 - 2² = 129225510917 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is the 359480-th Hogben number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 129225510921.

It is not an unprimeable number, because it can be changed into a prime (129225510121) by changing a digit.

It is a nontrivial repunit in base 359479.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5384566 + ... + 5408511.

It is an arithmetic number, because the mean of its divisors is an integer number (11634938084).

Almost surely, 2^129225510921 is an apocalyptic number.

It is an amenable number.

129225510921 is a deficient number, since it is larger than the sum of its proper divisors (56933498423).

129225510921 is a wasteful number, since it uses less digits than its factorization.

129225510921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10793400.

The product of its (nonzero) digits is 32400, while the sum is 39.

It can be divided in two parts, 129225 and 510921, that added together give a triangular number (640146 = T₁₁₃₁).

The spelling of 129225510921 in words is "one hundred twenty-nine billion, two hundred twenty-five million, five hundred ten thousand, nine hundred twenty-one".