51561511 has 2 divisors, whose sum is σ = 51561512. Its totient is φ = 51561510.

The previous prime is 51561479. The next prime is 51561529. The reversal of 51561511 is 11516515.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51561511 - 2⁵ = 51561479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51561551) 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, 25780755 + 25780756.

It is an arithmetic number, because the mean of its divisors is an integer number (25780756).

Almost surely, 2^51561511 is an apocalyptic number.

51561511 is a deficient number, since it is larger than the sum of its proper divisors (1).

51561511 is an equidigital number, since it uses as much as digits as its factorization.

51561511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 750, while the sum is 25.

The square root of 51561511 is about 7180.6344427216. The cubic root of 51561511 is about 372.1990085405.

It can be divided in two parts, 515615 and 11, that multiplied together give a palindrome (5671765).

The spelling of 51561511 in words is "fifty-one million, five hundred sixty-one thousand, five hundred eleven".