139193809 has 2 divisors, whose sum is σ = 139193810. Its totient is φ = 139193808.

The previous prime is 139193797. The next prime is 139193843. The reversal of 139193809 is 908391931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 99440784 + 39753025 = 9972^2 + 6305^2 .

It is a cyclic number.

It is not a de Polignac number, because 139193809 - 2⁵ = 139193777 is a prime.

It is not a weakly prime, because it can be changed into another prime (139193849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69596904 + 69596905.

It is an arithmetic number, because the mean of its divisors is an integer number (69596905).

Almost surely, 2^139193809 is an apocalyptic number.

It is an amenable number.

139193809 is a deficient number, since it is larger than the sum of its proper divisors (1).

139193809 is an equidigital number, since it uses as much as digits as its factorization.

139193809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 43.

The square root of 139193809 is about 11798.0425918879. The cubic root of 139193809 is about 518.2507903929.

The spelling of 139193809 in words is "one hundred thirty-nine million, one hundred ninety-three thousand, eight hundred nine".