51080021 has 4 divisors (see below), whose sum is σ = 51100044. Its totient is φ = 51060000.

The previous prime is 51080011. The next prime is 51080041. The reversal of 51080021 is 12008015.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12008015 = 5 ⋅2401603.

It can be written as a sum of positive squares in 2 ways, for example, as 41088100 + 9991921 = 6410^2 + 3161^2 .

It is a cyclic number.

It is not a de Polignac number, because 51080021 - 2⁶ = 51079957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51080011) 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, 5510 + ... + 11511.

It is an arithmetic number, because the mean of its divisors is an integer number (12775011).

Almost surely, 2^51080021 is an apocalyptic number.

It is an amenable number.

51080021 is a deficient number, since it is larger than the sum of its proper divisors (20023).

51080021 is a wasteful number, since it uses less digits than its factorization.

51080021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20022.

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 51080021 is about 7147.0288232244. The cubic root of 51080021 is about 371.0368312981.

Adding to 51080021 its reverse (12008015), we get a palindrome (63088036).

The spelling of 51080021 in words is "fifty-one million, eighty thousand, twenty-one".