129942731 has 4 divisors (see below), whose sum is σ = 134134464. Its totient is φ = 125751000.

The previous prime is 129942677. The next prime is 129942737. The reversal of 129942731 is 137249921.

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

It is a cyclic number.

It is not a de Polignac number, because 129942731 - 2⁶ = 129942667 is a prime.

It is a super-2 number, since 2×129942731² = 33770226679476722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129942737) 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 in 3 ways as a sum of consecutive naturals, for example, 2095820 + ... + 2095881.

It is an arithmetic number, because the mean of its divisors is an integer number (33533616).

Almost surely, 2^129942731 is an apocalyptic number.

129942731 is a deficient number, since it is larger than the sum of its proper divisors (4191733).

129942731 is an equidigital number, since it uses as much as digits as its factorization.

129942731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4191732.

The product of its digits is 27216, while the sum is 38.

The square root of 129942731 is about 11399.2425625565. The cubic root of 129942731 is about 506.5053030021.

The spelling of 129942731 in words is "one hundred twenty-nine million, nine hundred forty-two thousand, seven hundred thirty-one".