51361013021 has 4 divisors (see below), whose sum is σ = 51361494972. Its totient is φ = 51360531072.

The previous prime is 51361012999. The next prime is 51361013027. The reversal of 51361013021 is 12031016315.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 30107455225 + 21253557796 = 173515^2 + 145786^2 .

It is a cyclic number.

It is not a de Polignac number, because 51361013021 - 2¹⁸ = 51360750877 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 (51361013027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2366 + ... + 320511.

It is an arithmetic number, because the mean of its divisors is an integer number (12840373743).

Almost surely, 2^51361013021 is an apocalyptic number.

It is an amenable number.

51361013021 is a deficient number, since it is larger than the sum of its proper divisors (481951).

51361013021 is a wasteful number, since it uses less digits than its factorization.

51361013021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 481950.

The product of its (nonzero) digits is 540, while the sum is 23.

Adding to 51361013021 its reverse (12031016315), we get a palindrome (63392029336).

The spelling of 51361013021 in words is "fifty-one billion, three hundred sixty-one million, thirteen thousand, twenty-one".