51115521 has 4 divisors (see below), whose sum is σ = 68154032. Its totient is φ = 34077012.

The previous prime is 51115513. The next prime is 51115523. The reversal of 51115521 is 12551115.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 51115521 - 2³ = 51115513 is a prime.

It is a super-2 number, since 2×51115521² = 5225592974202882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51115523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8519251 + ... + 8519256.

It is an arithmetic number, because the mean of its divisors is an integer number (17038508).

Almost surely, 2^51115521 is an apocalyptic number.

It is an amenable number.

51115521 is a deficient number, since it is larger than the sum of its proper divisors (17038511).

51115521 is a wasteful number, since it uses less digits than its factorization.

51115521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17038510.

The product of its digits is 250, while the sum is 21.

The square root of 51115521 is about 7149.5119413845. The cubic root of 51115521 is about 371.1227667710.

Adding to 51115521 its reverse (12551115), we get a palindrome (63666636).

The spelling of 51115521 in words is "fifty-one million, one hundred fifteen thousand, five hundred twenty-one".