139321561 has 2 divisors, whose sum is σ = 139321562. Its totient is φ = 139321560.

The previous prime is 139321543. The next prime is 139321601. The reversal of 139321561 is 165123931.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 109411600 + 29909961 = 10460^2 + 5469^2 .

It is a cyclic number.

It is not a de Polignac number, because 139321561 - 2¹⁹ = 138797273 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (139321531) 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, 69660780 + 69660781.

It is an arithmetic number, because the mean of its divisors is an integer number (69660781).

Almost surely, 2^139321561 is an apocalyptic number.

It is an amenable number.

139321561 is a deficient number, since it is larger than the sum of its proper divisors (1).

139321561 is an equidigital number, since it uses as much as digits as its factorization.

139321561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4860, while the sum is 31.

The square root of 139321561 is about 11803.4554686329. The cubic root of 139321561 is about 518.4092920070.

The spelling of 139321561 in words is "one hundred thirty-nine million, three hundred twenty-one thousand, five hundred sixty-one".