21231331013 has 4 divisors (see below), whose sum is σ = 21239521548. Its totient is φ = 21223140480.

The previous prime is 21231330971. The next prime is 21231331021. The reversal of 21231331013 is 31013313212.

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 7049617444 + 14181713569 = 83962^2 + 119087^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231331013 - 2¹⁰ = 21231329989 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 (21231334013) 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, 4091378 + ... + 4096563.

It is an arithmetic number, because the mean of its divisors is an integer number (5309880387).

Almost surely, 2^21231331013 is an apocalyptic number.

It is an amenable number.

21231331013 is a deficient number, since it is larger than the sum of its proper divisors (8190535).

21231331013 is an equidigital number, since it uses as much as digits as its factorization.

21231331013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8190534.

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 21231331013 its reverse (31013313212), we get a palindrome (52244644225).

The spelling of 21231331013 in words is "twenty-one billion, two hundred thirty-one million, three hundred thirty-one thousand, thirteen".