21222020212 has 24 divisors (see below), whose sum is σ = 37624786920. Its totient is φ = 10472745600.

The previous prime is 21222020153. The next prime is 21222020219. The reversal of 21222020212 is 21202022212.

It can be written as a sum of positive squares in 4 ways, for example, as 6416971236 + 14805048976 = 80106^2 + 121676^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222020219) 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, 45214 + ... + 210922.

It is an arithmetic number, because the mean of its divisors is an integer number (1567699455).

Almost surely, 2^21222020212 is an apocalyptic number.

It is an amenable number.

21222020212 is a deficient number, since it is larger than the sum of its proper divisors (16402766708).

21222020212 is a wasteful number, since it uses less digits than its factorization.

21222020212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166131 (or 166129 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21222020212 its reverse (21202022212), we get a palindrome (42424042424).

The spelling of 21222020212 in words is "twenty-one billion, two hundred twenty-two million, twenty thousand, two hundred twelve".