921621120121 has 9 divisors (see below), whose sum is σ = 997981946031. Its totient is φ = 850715667672.

The previous prime is 921621120089. The next prime is 921621120131. The reversal of 921621120121 is 121021126129.

The square root of 921621120121 is 960011.

It is a perfect power (a square), and thus also a powerful number.

921621120121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 136334485225 + 785286634896 = 369235^2 + 886164^2 .

It is not a de Polignac number, because 921621120121 - 2⁵ = 921621120089 is a prime.

It is a super-2 number, since 2×921621120121² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 921621120121.

It is not an unprimeable number, because it can be changed into a prime (921621120131) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 12443220 + ... + 12517066.

Almost surely, 2^921621120121 is an apocalyptic number.

921621120121 is the 960011-st square number.

921621120121 is the 480006-th centered octagonal number.

It is an amenable number.

921621120121 is a deficient number, since it is larger than the sum of its proper divisors (76360825910).

921621120121 is an frugal number, since it uses more digits than its factorization.

921621120121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147720 (or 73860 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 28.

The spelling of 921621120121 in words is "nine hundred twenty-one billion, six hundred twenty-one million, one hundred twenty thousand, one hundred twenty-one".