139187261 has 2 divisors, whose sum is σ = 139187262. Its totient is φ = 139187260.

The previous prime is 139187249. The next prime is 139187273. The reversal of 139187261 is 162781931.

139187261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (139187249) and next prime (139187273).

It can be written as a sum of positive squares in only one way, i.e., 123899161 + 15288100 = 11131^2 + 3910^2 .

It is a cyclic number.

It is not a de Polignac number, because 139187261 - 2⁶ = 139187197 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (139187291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69593630 + 69593631.

It is an arithmetic number, because the mean of its divisors is an integer number (69593631).

Almost surely, 2^139187261 is an apocalyptic number.

It is an amenable number.

139187261 is a deficient number, since it is larger than the sum of its proper divisors (1).

139187261 is an equidigital number, since it uses as much as digits as its factorization.

139187261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 38.

The square root of 139187261 is about 11797.7650849642. The cubic root of 139187261 is about 518.2426636919.

The spelling of 139187261 in words is "one hundred thirty-nine million, one hundred eighty-seven thousand, two hundred sixty-one".