51045821 has 2 divisors, whose sum is σ = 51045822. Its totient is φ = 51045820.

The previous prime is 51045817. The next prime is 51045847. The reversal of 51045821 is 12854015.

It is an a-pointer prime, because the next prime (51045847) can be obtained adding 51045821 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49857721 + 1188100 = 7061^2 + 1090^2 .

It is a cyclic number.

It is not a de Polignac number, because 51045821 - 2² = 51045817 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51042821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25522910 + 25522911.

It is an arithmetic number, because the mean of its divisors is an integer number (25522911).

Almost surely, 2^51045821 is an apocalyptic number.

It is an amenable number.

51045821 is a deficient number, since it is larger than the sum of its proper divisors (1).

51045821 is an equidigital number, since it uses as much as digits as its factorization.

51045821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 51045821 is about 7144.6358199701. The cubic root of 51045821 is about 370.9540050942.

Adding to 51045821 its reverse (12854015), we get a palindrome (63899836).

The spelling of 51045821 in words is "fifty-one million, forty-five thousand, eight hundred twenty-one".