51681401 has 2 divisors, whose sum is σ = 51681402. Its totient is φ = 51681400.

The previous prime is 51681379. The next prime is 51681403. The reversal of 51681401 is 10418615.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39438400 + 12243001 = 6280^2 + 3499^2 .

It is a cyclic number.

It is not a de Polignac number, because 51681401 - 2⁶ = 51681337 is a prime.

It is a Sophie Germain prime.

Together with 51681403, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (51681403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25840700 + 25840701.

It is an arithmetic number, because the mean of its divisors is an integer number (25840701).

Almost surely, 2^51681401 is an apocalyptic number.

It is an amenable number.

51681401 is a deficient number, since it is larger than the sum of its proper divisors (1).

51681401 is an equidigital number, since it uses as much as digits as its factorization.

51681401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 51681401 is about 7188.9777437408. The cubic root of 51681401 is about 372.4872623003.

The spelling of 51681401 in words is "fifty-one million, six hundred eighty-one thousand, four hundred one".