129749521 has 8 divisors (see below), whose sum is σ = 143337600. Its totient is φ = 116460240.

The previous prime is 129749489. The next prime is 129749527. The reversal of 129749521 is 125947921.

It is a happy number.

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 129749521 - 2⁵ = 129749489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (129749527) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73786 + ... + 75523.

It is an arithmetic number, because the mean of its divisors is an integer number (17917200).

Almost surely, 2^129749521 is an apocalyptic number.

129749521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

129749521 is a deficient number, since it is larger than the sum of its proper divisors (13588079).

129749521 is a wasteful number, since it uses less digits than its factorization.

129749521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149399.

The product of its digits is 45360, while the sum is 40.

The square root of 129749521 is about 11390.7647241087. The cubic root of 129749521 is about 506.2541399651.

The spelling of 129749521 in words is "one hundred twenty-nine million, seven hundred forty-nine thousand, five hundred twenty-one".