51561311 has 2 divisors, whose sum is σ = 51561312. Its totient is φ = 51561310.

The previous prime is 51561281. The next prime is 51561317. The reversal of 51561311 is 11316515.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51561311 - 2⁶ = 51561247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51561317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25780655 + 25780656.

It is an arithmetic number, because the mean of its divisors is an integer number (25780656).

Almost surely, 2^51561311 is an apocalyptic number.

51561311 is a deficient number, since it is larger than the sum of its proper divisors (1).

51561311 is an equidigital number, since it uses as much as digits as its factorization.

51561311 is an evil number, because the sum of its binary digits is even.

The product of its digits is 450, while the sum is 23.

The square root of 51561311 is about 7180.6205163621. The cubic root of 51561311 is about 372.1985273037.

Adding to 51561311 its reverse (11316515), we get a palindrome (62877826).

The spelling of 51561311 in words is "fifty-one million, five hundred sixty-one thousand, three hundred eleven".