21220210121 has 4 divisors (see below), whose sum is σ = 23149320144. Its totient is φ = 19291100100.

The previous prime is 21220210087. The next prime is 21220210133. The reversal of 21220210121 is 12101202212.

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 21220210121 - 2²⁶ = 21153101257 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21220210096 and 21220210105.

It is not an unprimeable number, because it can be changed into a prime (21220210171) 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, 964554995 + ... + 964555016.

It is an arithmetic number, because the mean of its divisors is an integer number (5787330036).

Almost surely, 2^21220210121 is an apocalyptic number.

It is an amenable number.

21220210121 is a deficient number, since it is larger than the sum of its proper divisors (1929110023).

21220210121 is a wasteful number, since it uses less digits than its factorization.

21220210121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1929110022.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21220210121 its reverse (12101202212), we get a palindrome (33321412333).

The spelling of 21220210121 in words is "twenty-one billion, two hundred twenty million, two hundred ten thousand, one hundred twenty-one".