51220251 has 6 divisors (see below), whose sum is σ = 73984820. Its totient is φ = 34146828.

The previous prime is 51220223. The next prime is 51220291. The reversal of 51220251 is 15202215.

It is not a de Polignac number, because 51220251 - 2¹⁵ = 51187483 is a prime.

It is a super-3 number, since 3×51220251³ (a number of 24 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51220291) 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, 2845561 + ... + 2845578.

Almost surely, 2^51220251 is an apocalyptic number.

51220251 is a deficient number, since it is larger than the sum of its proper divisors (22764569).

51220251 is a wasteful number, since it uses less digits than its factorization.

51220251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5691145 (or 5691142 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 51220251 is about 7156.8324697453. The cubic root of 51220251 is about 371.3760569106.

Adding to 51220251 its reverse (15202215), we get a palindrome (66422466).

The spelling of 51220251 in words is "fifty-one million, two hundred twenty thousand, two hundred fifty-one".