139797509 has 4 divisors (see below), whose sum is σ = 141766560. Its totient is φ = 137828460.

The previous prime is 139797503. The next prime is 139797527. The reversal of 139797509 is 905797931.

139797509 = 347² + 348² + ... + 772².

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 139797509 - 2⁸ = 139797253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139797503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 984419 + ... + 984560.

It is an arithmetic number, because the mean of its divisors is an integer number (35441640).

Almost surely, 2^139797509 is an apocalyptic number.

It is an amenable number.

139797509 is a deficient number, since it is larger than the sum of its proper divisors (1969051).

139797509 is an equidigital number, since it uses as much as digits as its factorization.

139797509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1969050.

The product of its (nonzero) digits is 535815, while the sum is 50.

The square root of 139797509 is about 11823.5996633851. The cubic root of 139797509 is about 518.9989481257.

The spelling of 139797509 in words is "one hundred thirty-nine million, seven hundred ninety-seven thousand, five hundred nine".