21220012 has 36 divisors (see below), whose sum is σ = 43235640. Its totient is φ = 9074560.

The previous prime is 21219997. The next prime is 21220019. The reversal of 21220012 is 21002212.

It is not an unprimeable number, because it can be changed into a prime (21220019) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6939 + ... + 9517.

It is an arithmetic number, because the mean of its divisors is an integer number (1200990).

Almost surely, 2^21220012 is an apocalyptic number.

21220012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21220012 is an abundant number, since it is smaller than the sum of its proper divisors (22015628).

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

21220012 is a wasteful number, since it uses less digits than its factorization.

21220012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2622 (or 2609 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 21220012 is about 4606.5184250147. The cubic root of 21220012 is about 276.8525587377.

Adding to 21220012 its reverse (21002212), we get a palindrome (42222224).

It can be divided in two parts, 212200 and 12, that added together give a palindrome (212212).

The spelling of 21220012 in words is "twenty-one million, two hundred twenty thousand, twelve".