51705139 has 2 divisors, whose sum is σ = 51705140. Its totient is φ = 51705138.

The previous prime is 51705119. The next prime is 51705151. The reversal of 51705139 is 93150715.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51705139 - 2⁵ = 51705107 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51705139.

It is not a weakly prime, because it can be changed into another prime (51705119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25852569 + 25852570.

It is an arithmetic number, because the mean of its divisors is an integer number (25852570).

Almost surely, 2^51705139 is an apocalyptic number.

51705139 is a deficient number, since it is larger than the sum of its proper divisors (1).

51705139 is an equidigital number, since it uses as much as digits as its factorization.

51705139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4725, while the sum is 31.

The square root of 51705139 is about 7190.6285538887. The cubic root of 51705139 is about 372.5442831308.

The spelling of 51705139 in words is "fifty-one million, seven hundred five thousand, one hundred thirty-nine".