51381251 has 2 divisors, whose sum is σ = 51381252. Its totient is φ = 51381250.

The previous prime is 51381247. The next prime is 51381257. The reversal of 51381251 is 15218315.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51381251 - 2² = 51381247 is a prime.

It is a super-3 number, since 3×51381251³ (a number of 24 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51381251.

It is not a weakly prime, because it can be changed into another prime (51381257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25690625 + 25690626.

It is an arithmetic number, because the mean of its divisors is an integer number (25690626).

Almost surely, 2^51381251 is an apocalyptic number.

51381251 is a deficient number, since it is larger than the sum of its proper divisors (1).

51381251 is an equidigital number, since it uses as much as digits as its factorization.

51381251 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1200, while the sum is 26.

The square root of 51381251 is about 7168.0716374768. The cubic root of 51381251 is about 371.7647638889.

Adding to 51381251 its reverse (15218315), we get a palindrome (66599566).

The spelling of 51381251 in words is "fifty-one million, three hundred eighty-one thousand, two hundred fifty-one".