51110021 has 4 divisors (see below), whose sum is σ = 51228492. Its totient is φ = 50991552.

The previous prime is 51110011. The next prime is 51110023. The reversal of 51110021 is 12001115.

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 12496225 + 38613796 = 3535^2 + 6214^2 .

It is a cyclic number.

It is not a de Polignac number, because 51110021 - 2¹⁰ = 51108997 is a prime.

It is a super-2 number, since 2×51110021² = 5224468493240882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51109984 and 51110011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51110023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58586 + ... + 59451.

It is an arithmetic number, because the mean of its divisors is an integer number (12807123).

Almost surely, 2^51110021 is an apocalyptic number.

It is an amenable number.

51110021 is a deficient number, since it is larger than the sum of its proper divisors (118471).

51110021 is a wasteful number, since it uses less digits than its factorization.

51110021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118470.

The product of its (nonzero) digits is 10, while the sum is 11.

The square root of 51110021 is about 7149.1272893969. The cubic root of 51110021 is about 371.1094554297.

Adding to 51110021 its reverse (12001115), we get a palindrome (63111136).

The spelling of 51110021 in words is "fifty-one million, one hundred ten thousand, twenty-one".