139509731 has 2 divisors, whose sum is σ = 139509732. Its totient is φ = 139509730.

The previous prime is 139509709. The next prime is 139509739. The reversal of 139509731 is 137905931.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 139509731 - 2¹⁸ = 139247587 is a prime.

It is a super-2 number, since 2×139509731² = 38925930087384722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (139509739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69754865 + 69754866.

It is an arithmetic number, because the mean of its divisors is an integer number (69754866).

Almost surely, 2^139509731 is an apocalyptic number.

139509731 is a deficient number, since it is larger than the sum of its proper divisors (1).

139509731 is an equidigital number, since it uses as much as digits as its factorization.

139509731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25515, while the sum is 38.

The square root of 139509731 is about 11811.4237499126. The cubic root of 139509731 is about 518.6425777276.

The spelling of 139509731 in words is "one hundred thirty-nine million, five hundred nine thousand, seven hundred thirty-one".