20001221012 has 12 divisors (see below), whose sum is σ = 35012356596. Its totient is φ = 9997690560.

The previous prime is 20001220997. The next prime is 20001221039. The reversal of 20001221012 is 21012210002.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 5351507716 + 14649713296 = 73154^2 + 121036^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20001220984 and 20001221002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 714539 + ... + 742002.

It is an arithmetic number, because the mean of its divisors is an integer number (2917696383).

Almost surely, 2^20001221012 is an apocalyptic number.

It is an amenable number.

20001221012 is a deficient number, since it is larger than the sum of its proper divisors (15011135584).

20001221012 is a wasteful number, since it uses less digits than its factorization.

20001221012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1459978 (or 1459976 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20001221012 its reverse (21012210002), we get a palindrome (41013431014).

The spelling of 20001221012 in words is "twenty billion, one million, two hundred twenty-one thousand, twelve".