2121424221 has 16 divisors (see below), whose sum is σ = 3307825664. Its totient is φ = 1184050224.

The previous prime is 2121424183. The next prime is 2121424223. The reversal of 2121424221 is 1224241212.

It is not a de Polignac number, because 2121424221 - 2⁷ = 2121424093 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121424223) 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, 1173751 + ... + 1175556.

It is an arithmetic number, because the mean of its divisors is an integer number (206739104).

Almost surely, 2^2121424221 is an apocalyptic number.

2121424221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2121424221 is a deficient number, since it is larger than the sum of its proper divisors (1186401443).

2121424221 is a wasteful number, since it uses less digits than its factorization.

2121424221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2349360.

The product of its digits is 512, while the sum is 21.

The square root of 2121424221 is about 46058.9211879740. The cubic root of 2121424221 is about 1284.9192661759.

Adding to 2121424221 its reverse (1224241212), we get a palindrome (3345665433).

The spelling of 2121424221 in words is "two billion, one hundred twenty-one million, four hundred twenty-four thousand, two hundred twenty-one".