20202121101221 has 8 divisors (see below), whose sum is σ = 20361237186840. Its totient is φ = 20043566272512.

The previous prime is 20202121101187. The next prime is 20202121101223. The reversal of 20202121101221 is 12210112120202.

It can be written as a sum of positive squares in 4 ways, for example, as 3247614868996 + 16954506232225 = 1802114^2 + 4117585^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20202121101221 - 2¹⁴ = 20202121084837 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20202121101221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20202121101223) 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, 140241956 + ... + 140385933.

It is an arithmetic number, because the mean of its divisors is an integer number (2545154648355).

Almost surely, 2^{20202121101221} is an apocalyptic number.

It is an amenable number.

20202121101221 is a deficient number, since it is larger than the sum of its proper divisors (159116085619).

20202121101221 is a wasteful number, since it uses less digits than its factorization.

20202121101221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280628455.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 20202121101221 its reverse (12210112120202), we get a palindrome (32412233221423).

The spelling of 20202121101221 in words is "twenty trillion, two hundred two billion, one hundred twenty-one million, one hundred one thousand, two hundred twenty-one".