20012221021 has 12 divisors (see below), whose sum is σ = 21872581632. Its totient is φ = 18300159696.

The previous prime is 20012220983. The next prime is 20012221063. The reversal of 20012221021 is 12012221002.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-20012221021 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20012220992 and 20012221010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20012221091) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 535261 + ... + 571426.

It is an arithmetic number, because the mean of its divisors is an integer number (1822715136).

Almost surely, 2^20012221021 is an apocalyptic number.

It is an amenable number.

20012221021 is a deficient number, since it is larger than the sum of its proper divisors (1860360611).

20012221021 is a wasteful number, since it uses less digits than its factorization.

20012221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1106820 (or 1106807 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 20012221021 its reverse (12012221002), we get a palindrome (32024442023).

The spelling of 20012221021 in words is "twenty billion, twelve million, two hundred twenty-one thousand, twenty-one".