129646921 has 4 divisors (see below), whose sum is σ = 129704644. Its totient is φ = 129589200.

The previous prime is 129646919. The next prime is 129646931.

129646921 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 107931321 + 21715600 = 10389^2 + 4660^2 .

It is a cyclic number.

It is not a de Polignac number, because 129646921 - 2¹ = 129646919 is a prime.

It is a super-3 number, since 3×129646921³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129646931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25350 + ... + 30031.

It is an arithmetic number, because the mean of its divisors is an integer number (32426161).

Almost surely, 2^129646921 is an apocalyptic number.

It is an amenable number.

129646921 is a deficient number, since it is larger than the sum of its proper divisors (57723).

129646921 is an equidigital number, since it uses as much as digits as its factorization.

129646921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57722.

The product of its digits is 46656, while the sum is 40.

The square root of 129646921 is about 11386.2601849773. The cubic root of 129646921 is about 506.1206638865.

The spelling of 129646921 in words is "one hundred twenty-nine million, six hundred forty-six thousand, nine hundred twenty-one".