51681893 has 2 divisors, whose sum is σ = 51681894. Its totient is φ = 51681892.

The previous prime is 51681871. The next prime is 51681899. The reversal of 51681893 is 39818615.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 33721249 + 17960644 = 5807^2 + 4238^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51681893 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51681893.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51681899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25840946 + 25840947.

It is an arithmetic number, because the mean of its divisors is an integer number (25840947).

Almost surely, 2^51681893 is an apocalyptic number.

It is an amenable number.

51681893 is a deficient number, since it is larger than the sum of its proper divisors (1).

51681893 is an equidigital number, since it uses as much as digits as its factorization.

51681893 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 41.

The square root of 51681893 is about 7189.0119627109. The cubic root of 51681893 is about 372.4884443062.

The spelling of 51681893 in words is "fifty-one million, six hundred eighty-one thousand, eight hundred ninety-three".