51561061 has 2 divisors, whose sum is σ = 51561062. Its totient is φ = 51561060.

The previous prime is 51561049. The next prime is 51561127. The reversal of 51561061 is 16016515.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48650625 + 2910436 = 6975^2 + 1706^2 .

It is a cyclic number.

It is not a de Polignac number, because 51561061 - 2¹⁹ = 51036773 is a prime.

It is a super-2 number, since 2×51561061² = 5317086022891442, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51561031) 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, 25780530 + 25780531.

It is an arithmetic number, because the mean of its divisors is an integer number (25780531).

Almost surely, 2^51561061 is an apocalyptic number.

It is an amenable number.

51561061 is a deficient number, since it is larger than the sum of its proper divisors (1).

51561061 is an equidigital number, since it uses as much as digits as its factorization.

51561061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 51561061 is about 7180.6031083747. The cubic root of 51561061 is about 372.1979257558.

Adding to 51561061 its reverse (16016515), we get a palindrome (67577576).

It can be divided in two parts, 515 and 61061, that multiplied together give a triangular number (31446415 = T₇₉₃₀).

The spelling of 51561061 in words is "fifty-one million, five hundred sixty-one thousand, sixty-one".