51644251 has 2 divisors, whose sum is σ = 51644252. Its totient is φ = 51644250.

The previous prime is 51644231. The next prime is 51644279. The reversal of 51644251 is 15244615.

It is an a-pointer prime, because the next prime (51644279) can be obtained adding 51644251 to its sum of digits (28).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51644251 is a prime.

It is a super-2 number, since 2×51644251² = 5334257322702002, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (51644221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25822125 + 25822126.

It is an arithmetic number, because the mean of its divisors is an integer number (25822126).

Almost surely, 2^51644251 is an apocalyptic number.

51644251 is a deficient number, since it is larger than the sum of its proper divisors (1).

51644251 is an equidigital number, since it uses as much as digits as its factorization.

51644251 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4800, while the sum is 28.

The square root of 51644251 is about 7186.3934626487. The cubic root of 51644251 is about 372.3979895734.

Adding to 51644251 its reverse (15244615), we get a palindrome (66888866).

The spelling of 51644251 in words is "fifty-one million, six hundred forty-four thousand, two hundred fifty-one".