51561961 has 8 divisors (see below), whose sum is σ = 57446784. Its totient is φ = 45876720.

The previous prime is 51561919. The next prime is 51561973. The reversal of 51561961 is 16916515.

51561961 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51561961 - 2¹⁷ = 51430889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51561061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49350 + ... + 50383.

It is an arithmetic number, because the mean of its divisors is an integer number (7180848).

Almost surely, 2^51561961 is an apocalyptic number.

It is an amenable number.

51561961 is a deficient number, since it is larger than the sum of its proper divisors (5884823).

51561961 is a wasteful number, since it uses less digits than its factorization.

51561961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99791.

The product of its digits is 8100, while the sum is 34.

The square root of 51561961 is about 7180.6657769318. The cubic root of 51561961 is about 372.2000913189.

It can be divided in two parts, 5156 and 1961, that added together give a palindrome (7117).

The spelling of 51561961 in words is "fifty-one million, five hundred sixty-one thousand, nine hundred sixty-one".