129855558921 has 16 divisors (see below), whose sum is σ = 188909074368. Its totient is φ = 78688563200.

The previous prime is 129855558893. The next prime is 129855558923.

129855558921 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 129855558921 - 2¹⁵ = 129855526153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (129855558923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67896 + ... + 514121.

It is an arithmetic number, because the mean of its divisors is an integer number (11806817148).

Almost surely, 2^129855558921 is an apocalyptic number.

129855558921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

129855558921 is a deficient number, since it is larger than the sum of its proper divisors (59053515447).

129855558921 is a wasteful number, since it uses less digits than its factorization.

129855558921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588792.

The product of its digits is 12960000, while the sum is 60.

The spelling of 129855558921 in words is "one hundred twenty-nine billion, eight hundred fifty-five million, five hundred fifty-eight thousand, nine hundred twenty-one".