51781739 has 2 divisors, whose sum is σ = 51781740. Its totient is φ = 51781738.

The previous prime is 51781727. The next prime is 51781771. The reversal of 51781739 is 93718715.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51781739 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 51781696 and 51781705.

It is not a weakly prime, because it can be changed into another prime (51781799) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25890869 + 25890870.

It is an arithmetic number, because the mean of its divisors is an integer number (25890870).

Almost surely, 2^51781739 is an apocalyptic number.

51781739 is a deficient number, since it is larger than the sum of its proper divisors (1).

51781739 is an equidigital number, since it uses as much as digits as its factorization.

51781739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52920, while the sum is 41.

The square root of 51781739 is about 7195.9529598240. The cubic root of 51781739 is about 372.7281643463.

The spelling of 51781739 in words is "fifty-one million, seven hundred eighty-one thousand, seven hundred thirty-nine".