129840961 has 2 divisors, whose sum is σ = 129840962. Its totient is φ = 129840960.

The previous prime is 129840959. The next prime is 129840983. The reversal of 129840961 is 169048921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 106502400 + 23338561 = 10320^2 + 4831^2 .

It is a cyclic number.

It is not a de Polignac number, because 129840961 - 2¹ = 129840959 is a prime.

Together with 129840959, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (129850961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64920480 + 64920481.

It is an arithmetic number, because the mean of its divisors is an integer number (64920481).

Almost surely, 2^129840961 is an apocalyptic number.

It is an amenable number.

129840961 is a deficient number, since it is larger than the sum of its proper divisors (1).

129840961 is an equidigital number, since it uses as much as digits as its factorization.

129840961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 129840961 is about 11394.7777951130. Note that the first 4 decimals coincide. The cubic root of 129840961 is about 506.3730383057.

The spelling of 129840961 in words is "one hundred twenty-nine million, eight hundred forty thousand, nine hundred sixty-one".