129721499 has 8 divisors (see below), whose sum is σ = 133276752. Its totient is φ = 126184960.

The previous prime is 129721489. The next prime is 129721517. The reversal of 129721499 is 994127921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 129721499 - 2⁸ = 129721243 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129721429) 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 7 ways as a sum of consecutive naturals, for example, 9992 + ... + 18954.

It is an arithmetic number, because the mean of its divisors is an integer number (16659594).

Almost surely, 2^129721499 is an apocalyptic number.

129721499 is a deficient number, since it is larger than the sum of its proper divisors (3555253).

129721499 is an equidigital number, since it uses as much as digits as its factorization.

129721499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9357.

The product of its digits is 81648, while the sum is 44.

The square root of 129721499 is about 11389.5346261382. The cubic root of 129721499 is about 506.2176921109.

The spelling of 129721499 in words is "one hundred twenty-nine million, seven hundred twenty-one thousand, four hundred ninety-nine".