21361502321 has 4 divisors (see below), whose sum is σ = 21409078500. Its totient is φ = 21313926144.

The previous prime is 21361502297. The next prime is 21361502359. The reversal of 21361502321 is 12320516312.

It is a happy number.

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 17209504225 + 4151998096 = 131185^2 + 64436^2 .

It is a cyclic number.

It is not a de Polignac number, because 21361502321 - 2⁶ = 21361502257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21361502521) 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, 23787416 + ... + 23788313.

It is an arithmetic number, because the mean of its divisors is an integer number (5352269625).

Almost surely, 2^21361502321 is an apocalyptic number.

It is an amenable number.

21361502321 is a deficient number, since it is larger than the sum of its proper divisors (47576179).

21361502321 is an equidigital number, since it uses as much as digits as its factorization.

21361502321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47576178.

The product of its (nonzero) digits is 2160, while the sum is 26.

The spelling of 21361502321 in words is "twenty-one billion, three hundred sixty-one million, five hundred two thousand, three hundred twenty-one".