21020011212 has 36 divisors (see below), whose sum is σ = 49350187320. Its totient is φ = 6963579072.

The previous prime is 21020011141. The next prime is 21020011219. The reversal of 21020011212 is 21211002012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21020011219) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 285864 + ... + 351792.

Almost surely, 2^21020011212 is an apocalyptic number.

It is an amenable number.

21020011212 is an abundant number, since it is smaller than the sum of its proper divisors (28330176108).

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

21020011212 is a wasteful number, since it uses less digits than its factorization.

21020011212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66262 (or 66097 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21020011212 its reverse (21211002012), we get a palindrome (42231013224).

The spelling of 21020011212 in words is "twenty-one billion, twenty million, eleven thousand, two hundred twelve".