721612111121 has 4 divisors (see below), whose sum is σ = 787213212144. Its totient is φ = 656011010100.

The previous prime is 721612111117. The next prime is 721612111127. The reversal of 721612111121 is 121111216127.

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 not a de Polignac number, because 721612111121 - 2² = 721612111117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721612111127) 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, 32800550495 + ... + 32800550516.

It is an arithmetic number, because the mean of its divisors is an integer number (196803303036).

Almost surely, 2^721612111121 is an apocalyptic number.

It is an amenable number.

721612111121 is a deficient number, since it is larger than the sum of its proper divisors (65601101023).

721612111121 is a wasteful number, since it uses less digits than its factorization.

721612111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65601101022.

The product of its digits is 336, while the sum is 26.

Adding to 721612111121 its reverse (121111216127), we get a palindrome (842723327248).

The spelling of 721612111121 in words is "seven hundred twenty-one billion, six hundred twelve million, one hundred eleven thousand, one hundred twenty-one".