129747491 has 4 divisors (see below), whose sum is σ = 131085192. Its totient is φ = 128409792.

The previous prime is 129747481. The next prime is 129747503. The reversal of 129747491 is 194747921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 194747921 = 31 ⋅6282191.

It is a cyclic number.

It is not a de Polignac number, because 129747491 - 2¹⁰ = 129746467 is a prime.

It is a super-2 number, since 2×129747491² = 33668822841590162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129747481) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 668705 + ... + 668898.

It is an arithmetic number, because the mean of its divisors is an integer number (32771298).

Almost surely, 2^129747491 is an apocalyptic number.

129747491 is a deficient number, since it is larger than the sum of its proper divisors (1337701).

129747491 is an equidigital number, since it uses as much as digits as its factorization.

129747491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1337700.

The product of its digits is 127008, while the sum is 44.

The square root of 129747491 is about 11390.6756164856. The cubic root of 129747491 is about 506.2514997466.

The spelling of 129747491 in words is "one hundred twenty-nine million, seven hundred forty-seven thousand, four hundred ninety-one".