51561505 has 4 divisors (see below), whose sum is σ = 61873812. Its totient is φ = 41249200.

The previous prime is 51561479. The next prime is 51561511. The reversal of 51561505 is 50516515.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 24770529 + 26790976 = 4977^2 + 5176^2 .

It is not a de Polignac number, because 51561505 - 2⁵ = 51561473 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5156146 + ... + 5156155.

It is an arithmetic number, because the mean of its divisors is an integer number (15468453).

Almost surely, 2^51561505 is an apocalyptic number.

It is an amenable number.

51561505 is a deficient number, since it is larger than the sum of its proper divisors (10312307).

51561505 is a wasteful number, since it uses less digits than its factorization.

51561505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10312306.

The product of its (nonzero) digits is 3750, while the sum is 28.

The square root of 51561505 is about 7180.6340249312. The cubic root of 51561505 is about 372.1989941034.

The spelling of 51561505 in words is "fifty-one million, five hundred sixty-one thousand, five hundred five".