51440251 has 2 divisors, whose sum is σ = 51440252. Its totient is φ = 51440250.

The previous prime is 51440237. The next prime is 51440273. The reversal of 51440251 is 15204415.

It is an a-pointer prime, because the next prime (51440273) can be obtained adding 51440251 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51440251 - 2¹¹ = 51438203 is a prime.

It is not a weakly prime, because it can be changed into another prime (51440551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25720125 + 25720126.

It is an arithmetic number, because the mean of its divisors is an integer number (25720126).

Almost surely, 2^51440251 is an apocalyptic number.

51440251 is a deficient number, since it is larger than the sum of its proper divisors (1).

51440251 is an equidigital number, since it uses as much as digits as its factorization.

51440251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 800, while the sum is 22.

The square root of 51440251 is about 7172.1859289899. The cubic root of 51440251 is about 371.9070059876.

Adding to 51440251 its reverse (15204415), we get a palindrome (66644666).

The spelling of 51440251 in words is "fifty-one million, four hundred forty thousand, two hundred fifty-one".