138721597 has 12 divisors (see below), whose sum is σ = 161699196. Its totient is φ = 118661760.

The previous prime is 138721577. The next prime is 138721633. The reversal of 138721597 is 795127831.

It can be written as a sum of positive squares in 2 ways, for example, as 101888836 + 36832761 = 10094^2 + 6069^2 .

It is not a de Polignac number, because 138721597 - 2¹⁹ = 138197309 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 (138721537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23893 + ... + 29125.

It is an arithmetic number, because the mean of its divisors is an integer number (13474933).

Almost surely, 2^138721597 is an apocalyptic number.

It is an amenable number.

138721597 is a deficient number, since it is larger than the sum of its proper divisors (22977599).

138721597 is an equidigital number, since it uses as much as digits as its factorization.

138721597 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5788 (or 5781 counting only the distinct ones).

The product of its digits is 105840, while the sum is 43.

The square root of 138721597 is about 11778.0132874776. The cubic root of 138721597 is about 517.6640748693.

The spelling of 138721597 in words is "one hundred thirty-eight million, seven hundred twenty-one thousand, five hundred ninety-seven".