139204561 has 2 divisors, whose sum is σ = 139204562. Its totient is φ = 139204560.

The previous prime is 139204547. The next prime is 139204607. The reversal of 139204561 is 165402931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 113550336 + 25654225 = 10656^2 + 5065^2 .

It is a cyclic number.

It is not a de Polignac number, because 139204561 - 2⁷ = 139204433 is a prime.

It is not a weakly prime, because it can be changed into another prime (139204511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69602280 + 69602281.

It is an arithmetic number, because the mean of its divisors is an integer number (69602281).

Almost surely, 2^139204561 is an apocalyptic number.

It is an amenable number.

139204561 is a deficient number, since it is larger than the sum of its proper divisors (1).

139204561 is an equidigital number, since it uses as much as digits as its factorization.

139204561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 139204561 is about 11798.4982518963. The cubic root of 139204561 is about 518.2641341114.

It can be divided in two parts, 13920 and 4561, that added together give a palindrome (18481).

The spelling of 139204561 in words is "one hundred thirty-nine million, two hundred four thousand, five hundred sixty-one".