129891645 has 96 divisors (see below), whose sum is σ = 264412512. Its totient is φ = 58392576.

The previous prime is 129891617. The next prime is 129891647. The reversal of 129891645 is 546198921.

It can be written as a sum of positive squares in 16 ways, for example, as 13704804 + 116186841 = 3702^2 + 10779^2 .

It is not a de Polignac number, because 129891645 - 2⁵ = 129891613 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 129891645.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129891647) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 367789 + ... + 368141.

It is an arithmetic number, because the mean of its divisors is an integer number (2754297).

Almost surely, 2^129891645 is an apocalyptic number.

129891645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

129891645 is an abundant number, since it is smaller than the sum of its proper divisors (134520867).

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

129891645 is a wasteful number, since it uses less digits than its factorization.

129891645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431 (or 428 counting only the distinct ones).

The product of its digits is 155520, while the sum is 45.

The square root of 129891645 is about 11397.0015793629. The cubic root of 129891645 is about 506.4389180612.

The spelling of 129891645 in words is "one hundred twenty-nine million, eight hundred ninety-one thousand, six hundred forty-five".