129891001 has 2 divisors, whose sum is σ = 129891002. Its totient is φ = 129891000.

The previous prime is 129890987. The next prime is 129891043. The reversal of 129891001 is 100198921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 116208400 + 13682601 = 10780^2 + 3699^2 .

It is a cyclic number.

It is not a de Polignac number, because 129891001 - 2²¹ = 127793849 is a prime.

It is not a weakly prime, because it can be changed into another prime (129891061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64945500 + 64945501.

It is an arithmetic number, because the mean of its divisors is an integer number (64945501).

Almost surely, 2^129891001 is an apocalyptic number.

It is an amenable number.

129891001 is a deficient number, since it is larger than the sum of its proper divisors (1).

129891001 is an equidigital number, since it uses as much as digits as its factorization.

129891001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 129891001 is about 11396.9733262827. The cubic root of 129891001 is about 506.4380810887.

The spelling of 129891001 in words is "one hundred twenty-nine million, eight hundred ninety-one thousand, one".