51000561 has 12 divisors (see below), whose sum is σ = 78001092. Its totient is φ = 32000256.

The previous prime is 51000559. The next prime is 51000571. The reversal of 51000561 is 16500015.

51000561 is a `hidden beast` number, since 5 + 100 + 0 + 561 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 29322225 + 21678336 = 5415^2 + 4656^2 .

It is not a de Polignac number, because 51000561 - 2¹ = 51000559 is a prime.

51000561 is a modest number, since divided by 561 gives 51 as remainder.

It is not an unprimeable number, because it can be changed into a prime (51000511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 166516 + ... + 166821.

It is an arithmetic number, because the mean of its divisors is an integer number (6500091).

Almost surely, 2^51000561 is an apocalyptic number.

51000561 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

51000561 is a deficient number, since it is larger than the sum of its proper divisors (27000531).

51000561 is a wasteful number, since it uses less digits than its factorization.

51000561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333360 (or 333357 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 18.

The square root of 51000561 is about 7141.4677062912. The cubic root of 51000561 is about 370.8443366792.

Adding to 51000561 its reverse (16500015), we get a palindrome (67500576).

The spelling of 51000561 in words is "fifty-one million, five hundred sixty-one", and thus it is an aban number.