51420321 has 6 divisors (see below), whose sum is σ = 74273810. Its totient is φ = 34280208.

The previous prime is 51420319. The next prime is 51420331. The reversal of 51420321 is 12302415.

It can be written as a sum of positive squares in only one way, i.e., 50253921 + 1166400 = 7089^2 + 1080^2 .

It is not a de Polignac number, because 51420321 - 2¹ = 51420319 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51420294 and 51420303.

It is not an unprimeable number, because it can be changed into a prime (51420301) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2856676 + ... + 2856693.

Almost surely, 2^51420321 is an apocalyptic number.

It is an amenable number.

51420321 is a deficient number, since it is larger than the sum of its proper divisors (22853489).

51420321 is a wasteful number, since it uses less digits than its factorization.

51420321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5713375 (or 5713372 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 51420321 is about 7170.7963992851. The cubic root of 51420321 is about 371.8589692593.

Adding to 51420321 its reverse (12302415), we get a palindrome (63722736).

The spelling of 51420321 in words is "fifty-one million, four hundred twenty thousand, three hundred twenty-one".