21210222121 has 8 divisors (see below), whose sum is σ = 23320617984. Its totient is φ = 19130191920.

The previous prime is 21210222113. The next prime is 21210222157. The reversal of 21210222121 is 12122201212.

It is a happy number.

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 21210222121 - 2³ = 21210222113 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21210222095 and 21210222104.

It is not an unprimeable number, because it can be changed into a prime (21210222421) 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, 7589950 + ... + 7592743.

It is an arithmetic number, because the mean of its divisors is an integer number (2915077248).

Almost surely, 2^21210222121 is an apocalyptic number.

It is an amenable number.

21210222121 is a deficient number, since it is larger than the sum of its proper divisors (2110395863).

21210222121 is a wasteful number, since it uses less digits than its factorization.

21210222121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15182831.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21210222121 its reverse (12122201212), we get a palindrome (33332423333).

The spelling of 21210222121 in words is "twenty-one billion, two hundred ten million, two hundred twenty-two thousand, one hundred twenty-one".