51836821 has 2 divisors, whose sum is σ = 51836822. Its totient is φ = 51836820.

The previous prime is 51836797. The next prime is 51836843. The reversal of 51836821 is 12863815.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49196196 + 2640625 = 7014^2 + 1625^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51836821 is a prime.

It is a super-2 number, since 2×51836821² = 5374112022772082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51836221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25918410 + 25918411.

It is an arithmetic number, because the mean of its divisors is an integer number (25918411).

Almost surely, 2^51836821 is an apocalyptic number.

It is an amenable number.

51836821 is a deficient number, since it is larger than the sum of its proper divisors (1).

51836821 is an equidigital number, since it uses as much as digits as its factorization.

51836821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 34.

The square root of 51836821 is about 7199.7792327265. The cubic root of 51836821 is about 372.8602787283.

The spelling of 51836821 in words is "fifty-one million, eight hundred thirty-six thousand, eight hundred twenty-one".