21021220013 has 8 divisors (see below), whose sum is σ = 21316327200. Its totient is φ = 20727109168.

The previous prime is 21021220007. The next prime is 21021220039. The reversal of 21021220013 is 31002212012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21021220013 - 2¹⁸ = 21020957869 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21021220013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021220313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 206543 + ... + 291036.

It is an arithmetic number, because the mean of its divisors is an integer number (2664540900).

Almost surely, 2^21021220013 is an apocalyptic number.

It is an amenable number.

21021220013 is a deficient number, since it is larger than the sum of its proper divisors (295107187).

21021220013 is an equidigital number, since it uses as much as digits as its factorization.

21021220013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 498171.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21021220013 its reverse (31002212012), we get a palindrome (52023432025).

The spelling of 21021220013 in words is "twenty-one billion, twenty-one million, two hundred twenty thousand, thirteen".