21221020012 has 48 divisors (see below), whose sum is σ = 39597647040. Its totient is φ = 9928675328.

The previous prime is 21221019979. The next prime is 21221020021. The reversal of 21221020012 is 21002012212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21221019974 and 21221020001.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1715064 + ... + 1727392.

It is an arithmetic number, because the mean of its divisors is an integer number (824950980).

Almost surely, 2^21221020012 is an apocalyptic number.

It is an amenable number.

21221020012 is a deficient number, since it is larger than the sum of its proper divisors (18376627028).

21221020012 is a wasteful number, since it uses less digits than its factorization.

21221020012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12762 (or 12760 counting only the distinct ones).

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

Adding to 21221020012 its reverse (21002012212), we get a palindrome (42223032224).

The spelling of 21221020012 in words is "twenty-one billion, two hundred twenty-one million, twenty thousand, twelve".