21315520220213 has 4 divisors (see below), whose sum is σ = 21633662313120. Its totient is φ = 20997378127308.

The previous prime is 21315520220179. The next prime is 21315520220233. The reversal of 21315520220213 is 31202202551312.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21315520220213 - 2¹⁸ = 21315519958069 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315520220233) 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 3 ways as a sum of consecutive naturals, for example, 159071046353 + ... + 159071046486.

It is an arithmetic number, because the mean of its divisors is an integer number (5408415578280).

Almost surely, 2^{21315520220213} is an apocalyptic number.

It is an amenable number.

21315520220213 is a deficient number, since it is larger than the sum of its proper divisors (318142092907).

21315520220213 is an equidigital number, since it uses as much as digits as its factorization.

21315520220213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318142092906.

The product of its (nonzero) digits is 7200, while the sum is 29.

Adding to 21315520220213 its reverse (31202202551312), we get a palindrome (52517722771525).

The spelling of 21315520220213 in words is "twenty-one trillion, three hundred fifteen billion, five hundred twenty million, two hundred twenty thousand, two hundred thirteen".