21211210121 has 8 divisors (see below), whose sum is σ = 22604361984. Its totient is φ = 19857302080.

The previous prime is 21211210109. The next prime is 21211210133. The reversal of 21211210121 is 12101211212.

It is an interprime number because it is at equal distance from previous prime (21211210109) and next prime (21211210133).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21211210121 - 2¹⁴ = 21211193737 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21211210096 and 21211210105.

It is not an unprimeable number, because it can be changed into a prime (21211210021) 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, 9809840 + ... + 9812001.

It is an arithmetic number, because the mean of its divisors is an integer number (2825545248).

Almost surely, 2^21211210121 is an apocalyptic number.

It is an amenable number.

21211210121 is a deficient number, since it is larger than the sum of its proper divisors (1393151863).

21211210121 is a wasteful number, since it uses less digits than its factorization.

21211210121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19621911.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21211210121 its reverse (12101211212), we get a palindrome (33312421333).

The spelling of 21211210121 in words is "twenty-one billion, two hundred eleven million, two hundred ten thousand, one hundred twenty-one".