51971281 has 2 divisors, whose sum is σ = 51971282. Its totient is φ = 51971280.

The previous prime is 51971279. The next prime is 51971333. The reversal of 51971281 is 18217915.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51969681 + 1600 = 7209^2 + 40^2 .

It is a cyclic number.

It is not a de Polignac number, because 51971281 - 2¹ = 51971279 is a prime.

It is a super-2 number, since 2×51971281² = 5402028097561922, which contains 22 as substring.

Together with 51971279, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (51971201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25985640 + 25985641.

It is an arithmetic number, because the mean of its divisors is an integer number (25985641).

Almost surely, 2^51971281 is an apocalyptic number.

It is an amenable number.

51971281 is a deficient number, since it is larger than the sum of its proper divisors (1).

51971281 is an equidigital number, since it uses as much as digits as its factorization.

51971281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5040, while the sum is 34.

The square root of 51971281 is about 7209.1109715415. The cubic root of 51971281 is about 373.1823889330.

The spelling of 51971281 in words is "fifty-one million, nine hundred seventy-one thousand, two hundred eighty-one".