21012213021 has 16 divisors (see below), whose sum is σ = 28069200000. Its totient is φ = 13981713408.

The previous prime is 21012213011. The next prime is 21012213043. The reversal of 21012213021 is 12031221012.

It is not a de Polignac number, because 21012213021 - 2⁶ = 21012212957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012213011) 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 15 ways as a sum of consecutive naturals, for example, 4227880 + ... + 4232846.

It is an arithmetic number, because the mean of its divisors is an integer number (1754325000).

Almost surely, 2^21012213021 is an apocalyptic number.

It is an amenable number.

21012213021 is a deficient number, since it is larger than the sum of its proper divisors (7056986979).

21012213021 is a wasteful number, since it uses less digits than its factorization.

21012213021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7348.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21012213021 its reverse (12031221012), we get a palindrome (33043434033).

It can be divided in two parts, 2101 and 2213021, that added together give a palindrome (2215122).

The spelling of 21012213021 in words is "twenty-one billion, twelve million, two hundred thirteen thousand, twenty-one".