129921913 has 4 divisors (see below), whose sum is σ = 141733008. Its totient is φ = 118110820.

The previous prime is 129921893. The next prime is 129921919. The reversal of 129921913 is 319129921.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-129921913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129921919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5905531 + ... + 5905552.

It is an arithmetic number, because the mean of its divisors is an integer number (35433252).

Almost surely, 2^129921913 is an apocalyptic number.

It is an amenable number.

129921913 is a deficient number, since it is larger than the sum of its proper divisors (11811095).

129921913 is a wasteful number, since it uses less digits than its factorization.

129921913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11811094.

The product of its digits is 8748, while the sum is 37.

The square root of 129921913 is about 11398.3293951351. The cubic root of 129921913 is about 506.4782526483.

The spelling of 129921913 in words is "one hundred twenty-nine million, nine hundred twenty-one thousand, nine hundred thirteen".