51205521 has 32 divisors (see below), whose sum is σ = 75644928. Its totient is φ = 30697920.

The previous prime is 51205519. The next prime is 51205541. The reversal of 51205521 is 12550215.

It is not a de Polignac number, because 51205521 - 2¹ = 51205519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51205501) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 78820 + ... + 79466.

It is an arithmetic number, because the mean of its divisors is an integer number (2363904).

Almost surely, 2^51205521 is an apocalyptic number.

It is an amenable number.

51205521 is a deficient number, since it is larger than the sum of its proper divisors (24439407).

51205521 is a wasteful number, since it uses less digits than its factorization.

51205521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741.

The product of its (nonzero) digits is 500, while the sum is 21.

The square root of 51205521 is about 7155.8033092030. The cubic root of 51205521 is about 371.3404531947.

Adding to 51205521 its reverse (12550215), we get a palindrome (63755736).

The spelling of 51205521 in words is "fifty-one million, two hundred five thousand, five hundred twenty-one".