21200232121 has 4 divisors (see below), whose sum is σ = 21200733952. Its totient is φ = 21199730292.

The previous prime is 21200232107. The next prime is 21200232127. The reversal of 21200232121 is 12123200212.

It is a happy number.

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 21200232121 - 2¹⁷ = 21200101049 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21200232095 and 21200232104.

It is not an unprimeable number, because it can be changed into a prime (21200232127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 181065 + ... + 274198.

It is an arithmetic number, because the mean of its divisors is an integer number (5300183488).

Almost surely, 2^21200232121 is an apocalyptic number.

It is an amenable number.

21200232121 is a deficient number, since it is larger than the sum of its proper divisors (501831).

21200232121 is an equidigital number, since it uses as much as digits as its factorization.

21200232121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501830.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21200232121 its reverse (12123200212), we get a palindrome (33323432333).

The spelling of 21200232121 in words is "twenty-one billion, two hundred million, two hundred thirty-two thousand, one hundred twenty-one".