21231221313 has 8 divisors (see below), whose sum is σ = 28488603328. Its totient is φ = 14063993424.

The previous prime is 21231221287. The next prime is 21231221321. The reversal of 21231221313 is 31312213212.

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

It is not a de Polignac number, because 21231221313 - 2¹⁰ = 21231220289 is a prime.

It is a super-3 number, since 3×21231221313³ (a number of 32 digits) contains 333 as substring.

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 21231221313.

It is not an unprimeable number, because it can be changed into a prime (21231221393) 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, 22537981 + ... + 22538922.

It is an arithmetic number, because the mean of its divisors is an integer number (3561075416).

Almost surely, 2^21231221313 is an apocalyptic number.

It is an amenable number.

21231221313 is a deficient number, since it is larger than the sum of its proper divisors (7257382015).

21231221313 is a wasteful number, since it uses less digits than its factorization.

21231221313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45077063.

The product of its digits is 432, while the sum is 21.

Adding to 21231221313 its reverse (31312213212), we get a palindrome (52543434525).

The spelling of 21231221313 in words is "twenty-one billion, two hundred thirty-one million, two hundred twenty-one thousand, three hundred thirteen".