129387491 has 2 divisors, whose sum is σ = 129387492. Its totient is φ = 129387490.

The previous prime is 129387481. The next prime is 129387497. The reversal of 129387491 is 194783921.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129387491 is a prime.

It is a super-2 number, since 2×129387491² = 33482245654550162, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (129387497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64693745 + 64693746.

It is an arithmetic number, because the mean of its divisors is an integer number (64693746).

Almost surely, 2^129387491 is an apocalyptic number.

129387491 is a deficient number, since it is larger than the sum of its proper divisors (1).

129387491 is an equidigital number, since it uses as much as digits as its factorization.

129387491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 44.

The square root of 129387491 is about 11374.8622409241. The cubic root of 129387491 is about 505.7828475014.

The spelling of 129387491 in words is "one hundred twenty-nine million, three hundred eighty-seven thousand, four hundred ninety-one".