21020210121 has 8 divisors (see below), whose sum is σ = 28130368384. Its totient is φ = 13961762640.

The previous prime is 21020210077. The next prime is 21020210129. The reversal of 21020210121 is 12101202012.

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

It is not a de Polignac number, because 21020210121 - 2¹¹ = 21020208073 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020210097 and 21020210106.

It is not an unprimeable number, because it can be changed into a prime (21020210129) 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, 12926746 + ... + 12928371.

It is an arithmetic number, because the mean of its divisors is an integer number (3516296048).

Almost surely, 2^21020210121 is an apocalyptic number.

It is an amenable number.

21020210121 is a deficient number, since it is larger than the sum of its proper divisors (7110158263).

21020210121 is a wasteful number, since it uses less digits than its factorization.

21020210121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25855391.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21020210121 its reverse (12101202012), we get a palindrome (33121412133).

The spelling of 21020210121 in words is "twenty-one billion, twenty million, two hundred ten thousand, one hundred twenty-one".