21020212020121 has 4 divisors (see below), whose sum is σ = 21333946527952. Its totient is φ = 20706477512292.

The previous prime is 21020212020109. The next prime is 21020212020131. The reversal of 21020212020121 is 12102021202012.

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 a de Polignac number, because none of the positive numbers 2^k-21020212020121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21020212020095 and 21020212020104.

It is not an unprimeable number, because it can be changed into a prime (21020212020131) 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, 156867253815 + ... + 156867253948.

It is an arithmetic number, because the mean of its divisors is an integer number (5333486631988).

Almost surely, 2^{21020212020121} is an apocalyptic number.

It is an amenable number.

21020212020121 is a deficient number, since it is larger than the sum of its proper divisors (313734507831).

21020212020121 is an equidigital number, since it uses as much as digits as its factorization.

21020212020121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313734507830.

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

Adding to 21020212020121 its reverse (12102021202012), we get a palindrome (33122233222133).

The spelling of 21020212020121 in words is "twenty-one trillion, twenty billion, two hundred twelve million, twenty thousand, one hundred twenty-one".