51645109 has 2 divisors, whose sum is σ = 51645110. Its totient is φ = 51645108.

The previous prime is 51645103. The next prime is 51645131. The reversal of 51645109 is 90154615.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43362225 + 8282884 = 6585^2 + 2878^2 .

It is a cyclic number.

It is not a de Polignac number, because 51645109 - 2⁹ = 51644597 is a prime.

It is equal to p_3093817 and since 51645109 and 3093817 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51645103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25822554 + 25822555.

It is an arithmetic number, because the mean of its divisors is an integer number (25822555).

Almost surely, 2^51645109 is an apocalyptic number.

It is an amenable number.

51645109 is a deficient number, since it is larger than the sum of its proper divisors (1).

51645109 is an equidigital number, since it uses as much as digits as its factorization.

51645109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 31.

The square root of 51645109 is about 7186.4531585477. The cubic root of 51645109 is about 372.4000518597.

The spelling of 51645109 in words is "fifty-one million, six hundred forty-five thousand, one hundred nine".