21022221012 has 96 divisors (see below), whose sum is σ = 56064661632. Its totient is φ = 6073491456.

The previous prime is 21022220983. The next prime is 21022221013. The reversal of 21022221012 is 21012222012.

It is a junction number, because it is equal to n+sod(n) for n = 21022220982 and 21022221000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022221013) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1139163 + ... + 1157469.

It is an arithmetic number, because the mean of its divisors is an integer number (584006892).

Almost surely, 2^21022221012 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21022221012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28032330816).

21022221012 is an abundant number, since it is smaller than the sum of its proper divisors (35042440620).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21022221012 is a wasteful number, since it uses less digits than its factorization.

21022221012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18777 (or 18775 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21022221012 its reverse (21012222012), we get a palindrome (42034443024).

The spelling of 21022221012 in words is "twenty-one billion, twenty-two million, two hundred twenty-one thousand, twelve".