20202021221 has 4 divisors (see below), whose sum is σ = 20671835712. Its totient is φ = 19732206732.

The previous prime is 20202021199. The next prime is 20202021269. The reversal of 20202021221 is 12212020202.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12212020202 = 2 ⋅6106010101.

It is a cyclic number.

It is not a de Polignac number, because 20202021221 - 2¹⁰ = 20202020197 is a prime.

It is a super-2 number, since 2×20202021221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20202021196 and 20202021205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20202021821) 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, 234907181 + ... + 234907266.

It is an arithmetic number, because the mean of its divisors is an integer number (5167958928).

Almost surely, 2^20202021221 is an apocalyptic number.

It is an amenable number.

20202021221 is a deficient number, since it is larger than the sum of its proper divisors (469814491).

20202021221 is an equidigital number, since it uses as much as digits as its factorization.

20202021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 469814490.

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 20202021221 its reverse (12212020202), we get a palindrome (32414041423).

It can be divided in two parts, 2020202 and 1221, that multiplied together give a palindrome (2466666642).

The spelling of 20202021221 in words is "twenty billion, two hundred two million, twenty-one thousand, two hundred twenty-one".