21012221013 has 48 divisors (see below), whose sum is σ = 33177009600. Its totient is φ = 11791954944.

The previous prime is 21012220969. The next prime is 21012221047. The reversal of 21012221013 is 31012221012.

It is not a de Polignac number, because 21012221013 - 2³² = 16717253717 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21012220983 and 21012221001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012221513) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3434245 + ... + 3440357.

It is an arithmetic number, because the mean of its divisors is an integer number (691187700).

Almost surely, 2^21012221013 is an apocalyptic number.

It is an amenable number.

21012221013 is a deficient number, since it is larger than the sum of its proper divisors (12164788587).

21012221013 is a wasteful number, since it uses less digits than its factorization.

21012221013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6546 (or 6539 counting only the distinct ones).

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

Adding to 21012221013 its reverse (31012221012), we get a palindrome (52024442025).

Subtracting 21012221013 from its reverse (31012221012), we obtain a palindrome (9999999999).

The spelling of 21012221013 in words is "twenty-one billion, twelve million, two hundred twenty-one thousand, thirteen".