21210021220313 has 4 divisors (see below), whose sum is σ = 21237602523060. Its totient is φ = 21182439917568.

The previous prime is 21210021220243. The next prime is 21210021220361. The reversal of 21210021220313 is 31302212001212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10660205410009 + 10549815810304 = 3264997^2 + 3248048^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210021220313 - 2¹² = 21210021216217 is a prime.

It is a super-2 number, since 2×21210021220313² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210021270313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13790650220 + ... + 13790651757.

It is an arithmetic number, because the mean of its divisors is an integer number (5309400630765).

Almost surely, 2^{21210021220313} is an apocalyptic number.

It is an amenable number.

21210021220313 is a deficient number, since it is larger than the sum of its proper divisors (27581302747).

21210021220313 is an equidigital number, since it uses as much as digits as its factorization.

21210021220313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27581302746.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 21210021220313 its reverse (31302212001212), we get a palindrome (52512233221525).

The spelling of 21210021220313 in words is "twenty-one trillion, two hundred ten billion, twenty-one million, two hundred twenty thousand, three hundred thirteen".