7122720121 has 16 divisors (see below), whose sum is σ = 7991597376. Its totient is φ = 6292000000.

The previous prime is 7122720103. The next prime is 7122720151. The reversal of 7122720121 is 1210272217.

It is a de Polignac number, because none of the positive numbers 2^k-7122720121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7122720151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81741 + ... + 144661.

It is an arithmetic number, because the mean of its divisors is an integer number (499474836).

Almost surely, 2^7122720121 is an apocalyptic number.

It is an amenable number.

7122720121 is a deficient number, since it is larger than the sum of its proper divisors (868877255).

7122720121 is a wasteful number, since it uses less digits than its factorization.

7122720121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63224.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 7122720121 is about 84396.2091624973. The cubic root of 7122720121 is about 1924.0453012423.

Adding to 7122720121 its reverse (1210272217), we get a palindrome (8332992338).

The spelling of 7122720121 in words is "seven billion, one hundred twenty-two million, seven hundred twenty thousand, one hundred twenty-one".