12506719661 has 2 divisors, whose sum is σ = 12506719662. Its totient is φ = 12506719660.

The previous prime is 12506719567. The next prime is 12506719691. The reversal of 12506719661 is 16691760521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12450319561 + 56400100 = 111581^2 + 7510^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12506719661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12506719691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6253359830 + 6253359831.

It is an arithmetic number, because the mean of its divisors is an integer number (6253359831).

Almost surely, 2^12506719661 is an apocalyptic number.

It is an amenable number.

12506719661 is a deficient number, since it is larger than the sum of its proper divisors (1).

12506719661 is an equidigital number, since it uses as much as digits as its factorization.

12506719661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 136080, while the sum is 44.

The spelling of 12506719661 in words is "twelve billion, five hundred six million, seven hundred nineteen thousand, six hundred sixty-one".