51312139 has 2 divisors, whose sum is σ = 51312140. Its totient is φ = 51312138.

The previous prime is 51312133. The next prime is 51312167. The reversal of 51312139 is 93121315.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51312139 - 2¹⁹ = 50787851 is a prime.

It is not a weakly prime, because it can be changed into another prime (51312133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25656069 + 25656070.

It is an arithmetic number, because the mean of its divisors is an integer number (25656070).

Almost surely, 2^51312139 is an apocalyptic number.

51312139 is a deficient number, since it is larger than the sum of its proper divisors (1).

51312139 is an equidigital number, since it uses as much as digits as its factorization.

51312139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 810, while the sum is 25.

The square root of 51312139 is about 7163.2491929291. The cubic root of 51312139 is about 371.5980043908.

The spelling of 51312139 in words is "fifty-one million, three hundred twelve thousand, one hundred thirty-nine".