51365381 has 4 divisors (see below), whose sum is σ = 54386892. Its totient is φ = 48343872.

The previous prime is 51365311. The next prime is 51365389. The reversal of 51365381 is 18356315.

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 20784481 + 30580900 = 4559^2 + 5530^2 .

It is a cyclic number.

It is not a de Polignac number, because 51365381 - 2¹⁸ = 51103237 is a prime.

It is a super-2 number, since 2×51365381² = 5276804730550322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51365389) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1510730 + ... + 1510763.

It is an arithmetic number, because the mean of its divisors is an integer number (13596723).

Almost surely, 2^51365381 is an apocalyptic number.

It is an amenable number.

51365381 is a deficient number, since it is larger than the sum of its proper divisors (3021511).

51365381 is a wasteful number, since it uses less digits than its factorization.

51365381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3021510.

The product of its digits is 10800, while the sum is 32.

The square root of 51365381 is about 7166.9645597003. The cubic root of 51365381 is about 371.7264845930.

The spelling of 51365381 in words is "fifty-one million, three hundred sixty-five thousand, three hundred eighty-one".