121720051 has 4 divisors (see below), whose sum is σ = 128880072. Its totient is φ = 114560032.

The previous prime is 121720031. The next prime is 121720069. The reversal of 121720051 is 150027121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 121720051 - 2¹⁵ = 121687283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121720031) 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, 3579985 + ... + 3580018.

It is an arithmetic number, because the mean of its divisors is an integer number (32220018).

Almost surely, 2^121720051 is an apocalyptic number.

121720051 is a deficient number, since it is larger than the sum of its proper divisors (7160021).

121720051 is an equidigital number, since it uses as much as digits as its factorization.

121720051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7160020.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 121720051 is about 11032.6810431554. The cubic root of 121720051 is about 495.5879162171.

Adding to 121720051 its reverse (150027121), we get a palindrome (271747172).

The spelling of 121720051 in words is "one hundred twenty-one million, seven hundred twenty thousand, fifty-one".