21230312121 has 12 divisors (see below), whose sum is σ = 30686704048. Its totient is φ = 14143988664.

The previous prime is 21230312107. The next prime is 21230312209. The reversal of 21230312121 is 12121303212.

21230312121 is a `hidden beast` number, since 2 + 1 + 230 + 312 + 121 = 666.

It is not a de Polignac number, because 21230312121 - 2⁶ = 21230312057 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21230312094 and 21230312103.

It is not an unprimeable number, because it can be changed into a prime (21230312101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 781975 + ... + 808668.

Almost surely, 2^21230312121 is an apocalyptic number.

It is an amenable number.

21230312121 is a deficient number, since it is larger than the sum of its proper divisors (9456391927).

21230312121 is a wasteful number, since it uses less digits than its factorization.

21230312121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1592132 (or 1592129 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21230312121 its reverse (12121303212), we get a palindrome (33351615333).

The spelling of 21230312121 in words is "twenty-one billion, two hundred thirty million, three hundred twelve thousand, one hundred twenty-one".