19756755661 has 2 divisors, whose sum is σ = 19756755662. Its totient is φ = 19756755660.

The previous prime is 19756755631. The next prime is 19756755677. The reversal of 19756755661 is 16655765791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12366774436 + 7389981225 = 111206^2 + 85965^2 .

It is a cyclic number.

It is not a de Polignac number, because 19756755661 - 2¹⁹ = 19756231373 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19756755596 and 19756755605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19756755611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9878377830 + 9878377831.

It is an arithmetic number, because the mean of its divisors is an integer number (9878377831).

Almost surely, 2^19756755661 is an apocalyptic number.

It is an amenable number.

19756755661 is a deficient number, since it is larger than the sum of its proper divisors (1).

19756755661 is an equidigital number, since it uses as much as digits as its factorization.

19756755661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11907000, while the sum is 58.

The spelling of 19756755661 in words is "nineteen billion, seven hundred fifty-six million, seven hundred fifty-five thousand, six hundred sixty-one".