139673561 has 2 divisors, whose sum is σ = 139673562. Its totient is φ = 139673560.

The previous prime is 139673533. The next prime is 139673563. The reversal of 139673561 is 165376931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 92833225 + 46840336 = 9635^2 + 6844^2 .

It is a cyclic number.

It is not a de Polignac number, because 139673561 - 2²² = 135479257 is a prime.

Together with 139673563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (139673563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69836780 + 69836781.

It is an arithmetic number, because the mean of its divisors is an integer number (69836781).

Almost surely, 2^139673561 is an apocalyptic number.

It is an amenable number.

139673561 is a deficient number, since it is larger than the sum of its proper divisors (1).

139673561 is an equidigital number, since it uses as much as digits as its factorization.

139673561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 102060, while the sum is 41.

The square root of 139673561 is about 11818.3569501010. The cubic root of 139673561 is about 518.8455169158.

The spelling of 139673561 in words is "one hundred thirty-nine million, six hundred seventy-three thousand, five hundred sixty-one".