121711721 has 4 divisors (see below), whose sum is σ = 128871252. Its totient is φ = 114552192.

The previous prime is 121711703. The next prime is 121711747. The reversal of 121711721 is 127117121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127117121 = 29 ⋅4383349.

It can be written as a sum of positive squares in 2 ways, for example, as 105349696 + 16362025 = 10264^2 + 4045^2 .

It is a cyclic number.

It is not a de Polignac number, because 121711721 - 2²² = 117517417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121711021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3579740 + ... + 3579773.

It is an arithmetic number, because the mean of its divisors is an integer number (32217813).

Almost surely, 2^121711721 is an apocalyptic number.

It is an amenable number.

121711721 is a deficient number, since it is larger than the sum of its proper divisors (7159531).

121711721 is an equidigital number, since it uses as much as digits as its factorization.

121711721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7159530.

The product of its digits is 196, while the sum is 23.

The square root of 121711721 is about 11032.3035219305. The cubic root of 121711721 is about 495.5766106530.

Adding to 121711721 its reverse (127117121), we get a palindrome (248828842).

The spelling of 121711721 in words is "one hundred twenty-one million, seven hundred eleven thousand, seven hundred twenty-one".