139587809 has 2 divisors, whose sum is σ = 139587810. Its totient is φ = 139587808.

The previous prime is 139587803. The next prime is 139587827. The reversal of 139587809 is 908785931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 102414400 + 37173409 = 10120^2 + 6097^2 .

It is an emirp because it is prime and its reverse (908785931) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139587809 is a prime.

It is not a weakly prime, because it can be changed into another prime (139587803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69793904 + 69793905.

It is an arithmetic number, because the mean of its divisors is an integer number (69793905).

Almost surely, 2^139587809 is an apocalyptic number.

It is an amenable number.

139587809 is a deficient number, since it is larger than the sum of its proper divisors (1).

139587809 is an equidigital number, since it uses as much as digits as its factorization.

139587809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 544320, while the sum is 50.

The square root of 139587809 is about 11814.7284776249. The cubic root of 139587809 is about 518.7393141651.

The spelling of 139587809 in words is "one hundred thirty-nine million, five hundred eighty-seven thousand, eight hundred nine".