2123121221 has 8 divisors (see below), whose sum is σ = 2299657080. Its totient is φ = 1948473792.

The previous prime is 2123121197. The next prime is 2123121241. The reversal of 2123121221 is 1221213212.

It can be written as a sum of positive squares in 4 ways, for example, as 159390625 + 1963730596 = 12625^2 + 44314^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2123121221 - 2⁶ = 2123121157 is a prime.

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 2123121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2123121241) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 469766 + ... + 474263.

It is an arithmetic number, because the mean of its divisors is an integer number (287457135).

Almost surely, 2^2123121221 is an apocalyptic number.

It is an amenable number.

2123121221 is a deficient number, since it is larger than the sum of its proper divisors (176535859).

2123121221 is a wasteful number, since it uses less digits than its factorization.

2123121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 944215.

The product of its digits is 96, while the sum is 17.

The square root of 2123121221 is about 46077.3395607863. The cubic root of 2123121221 is about 1285.2617918575.

Adding to 2123121221 its reverse (1221213212), we get a palindrome (3344334433).

It can be divided in two parts, 212312 and 1221, that multiplied together give a palindrome (259232952).

The spelling of 2123121221 in words is "two billion, one hundred twenty-three million, one hundred twenty-one thousand, two hundred twenty-one".