121721129 has 8 divisors (see below), whose sum is σ = 128325120. Its totient is φ = 115226496.

The previous prime is 121721113. The next prime is 121721141. The reversal of 121721129 is 921127121.

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 121721129 - 2⁴ = 121721113 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 121721098 and 121721107.

It is not an unprimeable number, because it can be changed into a prime (121721179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25049 + ... + 29510.

It is an arithmetic number, because the mean of its divisors is an integer number (16040640).

Almost surely, 2^121721129 is an apocalyptic number.

It is an amenable number.

121721129 is a deficient number, since it is larger than the sum of its proper divisors (6603991).

121721129 is an equidigital number, since it uses as much as digits as its factorization.

121721129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54679.

The product of its digits is 504, while the sum is 26.

The square root of 121721129 is about 11032.7298978993. The cubic root of 121721129 is about 495.5893792524.

The spelling of 121721129 in words is "one hundred twenty-one million, seven hundred twenty-one thousand, one hundred twenty-nine".