21381320512037 has 8 divisors (see below), whose sum is σ = 21738761742552. Its totient is φ = 21024102758400.

The previous prime is 21381320511997. The next prime is 21381320512039. The reversal of 21381320512037 is 73021502318312.

It is a Cunningham number, because it is equal to 4623994²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 695279139556 + 20686041372481 = 833834^2 + 4548191^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21381320512037 - 2³⁶ = 21312601035301 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 (21381320512039) 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 7 ways as a sum of consecutive naturals, for example, 55676264 + ... + 56058977.

It is an arithmetic number, because the mean of its divisors is an integer number (2717345217819).

Almost surely, 2^{21381320512037} is an apocalyptic number.

It is an amenable number.

21381320512037 is a deficient number, since it is larger than the sum of its proper divisors (357441230515).

21381320512037 is a wasteful number, since it uses less digits than its factorization.

21381320512037 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111738439.

The product of its (nonzero) digits is 60480, while the sum is 38.

The spelling of 21381320512037 in words is "twenty-one trillion, three hundred eighty-one billion, three hundred twenty million, five hundred twelve thousand, thirty-seven".