139188521 has 2 divisors, whose sum is σ = 139188522. Its totient is φ = 139188520.

The previous prime is 139188473. The next prime is 139188527. The reversal of 139188521 is 125881931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 88266025 + 50922496 = 9395^2 + 7136^2 .

It is a cyclic number.

It is not a de Polignac number, because 139188521 - 2¹⁸ = 138926377 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (139188527) 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 as a sum of consecutive naturals, namely, 69594260 + 69594261.

It is an arithmetic number, because the mean of its divisors is an integer number (69594261).

Almost surely, 2^139188521 is an apocalyptic number.

It is an amenable number.

139188521 is a deficient number, since it is larger than the sum of its proper divisors (1).

139188521 is an equidigital number, since it uses as much as digits as its factorization.

139188521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 38.

The square root of 139188521 is about 11797.8184847878. The cubic root of 139188521 is about 518.2442274935.

The spelling of 139188521 in words is "one hundred thirty-nine million, one hundred eighty-eight thousand, five hundred twenty-one".