51105105021 has 4 divisors (see below), whose sum is σ = 68140140032. Its totient is φ = 34070070012.

The previous prime is 51105105019. The next prime is 51105105059. The reversal of 51105105021 is 12050150115.

51105105021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 51105105021 - 2¹ = 51105105019 is a prime.

It is a super-2 number, since 2×51105105021² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51105105061) 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, 8517517501 + ... + 8517517506.

It is an arithmetic number, because the mean of its divisors is an integer number (17035035008).

Almost surely, 2^51105105021 is an apocalyptic number.

It is an amenable number.

51105105021 is a deficient number, since it is larger than the sum of its proper divisors (17035035011).

51105105021 is a wasteful number, since it uses less digits than its factorization.

51105105021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17035035010.

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

Adding to 51105105021 its reverse (12050150115), we get a palindrome (63155255136).

The spelling of 51105105021 in words is "fifty-one billion, one hundred five million, one hundred five thousand, twenty-one".