139897237 has 4 divisors (see below), whose sum is σ = 140257260. Its totient is φ = 139537216.

The previous prime is 139897213. The next prime is 139897243. The reversal of 139897237 is 732798931.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 732798931 = 5791 ⋅126541.

It can be written as a sum of positive squares in 2 ways, for example, as 50140561 + 89756676 = 7081^2 + 9474^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139897237 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139897837) 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 3 ways as a sum of consecutive naturals, for example, 179428 + ... + 180205.

It is an arithmetic number, because the mean of its divisors is an integer number (35064315).

Almost surely, 2^139897237 is an apocalyptic number.

It is an amenable number.

139897237 is a deficient number, since it is larger than the sum of its proper divisors (360023).

139897237 is an equidigital number, since it uses as much as digits as its factorization.

139897237 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360022.

The product of its digits is 571536, while the sum is 49.

The square root of 139897237 is about 11827.8162396953. The cubic root of 139897237 is about 519.1223323561.

The spelling of 139897237 in words is "one hundred thirty-nine million, eight hundred ninety-seven thousand, two hundred thirty-seven".