137666139661 has 2 divisors, whose sum is σ = 137666139662. Its totient is φ = 137666139660.

The previous prime is 137666139629. The next prime is 137666139671. The reversal of 137666139661 is 166931666731.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83640110436 + 54026029225 = 289206^2 + 232435^2 .

It is a cyclic number.

It is not a de Polignac number, because 137666139661 - 2⁵ = 137666139629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (137666139601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 68833069830 + 68833069831.

It is an arithmetic number, because the mean of its divisors is an integer number (68833069831).

Almost surely, 2^137666139661 is an apocalyptic number.

It is an amenable number.

137666139661 is a deficient number, since it is larger than the sum of its proper divisors (1).

137666139661 is an equidigital number, since it uses as much as digits as its factorization.

137666139661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4408992, while the sum is 55.

The spelling of 137666139661 in words is "one hundred thirty-seven billion, six hundred sixty-six million, one hundred thirty-nine thousand, six hundred sixty-one".