20012121221 has 8 divisors (see below), whose sum is σ = 21224546304. Its totient is φ = 18828223920.

The previous prime is 20012121209. The next prime is 20012121223. The reversal of 20012121221 is 12212121002.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20012121221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20012121196 and 20012121205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20012121223) 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, 7130501 + ... + 7133306.

It is an arithmetic number, because the mean of its divisors is an integer number (2653068288).

Almost surely, 2^20012121221 is an apocalyptic number.

It is an amenable number.

20012121221 is a deficient number, since it is larger than the sum of its proper divisors (1212425083).

20012121221 is a wasteful number, since it uses less digits than its factorization.

20012121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14263891.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 20012121221 its reverse (12212121002), we get a palindrome (32224242223).

The spelling of 20012121221 in words is "twenty billion, twelve million, one hundred twenty-one thousand, two hundred twenty-one".