51365821 has 16 divisors (see below), whose sum is σ = 56383488. Its totient is φ = 46512000.

The previous prime is 51365807. The next prime is 51365827. The reversal of 51365821 is 12856315.

It is a cyclic number.

It is not a de Polignac number, because 51365821 - 2⁹ = 51365309 is a prime.

It is a super-3 number, since 3×51365821³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51365827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 268836 + ... + 269026.

It is an arithmetic number, because the mean of its divisors is an integer number (3523968).

Almost surely, 2^51365821 is an apocalyptic number.

It is an amenable number.

51365821 is a deficient number, since it is larger than the sum of its proper divisors (5017667).

51365821 is a wasteful number, since it uses less digits than its factorization.

51365821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 492.

The product of its digits is 7200, while the sum is 31.

The square root of 51365821 is about 7166.9952560330. The cubic root of 51365821 is about 371.7275460030.

The spelling of 51365821 in words is "fifty-one million, three hundred sixty-five thousand, eight hundred twenty-one".