21221000012 has 12 divisors (see below), whose sum is σ = 37519603800. Its totient is φ = 10501113216.

The previous prime is 21220999973. The next prime is 21221000027. The reversal of 21221000012 is 21000012212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21220999957 and 21221000002.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27346262 + ... + 27347037.

It is an arithmetic number, because the mean of its divisors is an integer number (3126633650).

Almost surely, 2^21221000012 is an apocalyptic number.

It is an amenable number.

21221000012 is a deficient number, since it is larger than the sum of its proper divisors (16298603788).

21221000012 is a wasteful number, since it uses less digits than its factorization.

21221000012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54693400 (or 54693398 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21221000012 its reverse (21000012212), we get a palindrome (42221012224).

It can be divided in two parts, 212 and 21000012, that multiplied together give a palindrome (4452002544).

The spelling of 21221000012 in words is "twenty-one billion, two hundred twenty-one million, twelve", and thus it is an aban number.