19965657623 has 2 divisors, whose sum is σ = 19965657624. Its totient is φ = 19965657622.

The previous prime is 19965657581. The next prime is 19965657683. The reversal of 19965657623 is 32675656991.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19965657623 - 2⁸ = 19965657367 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19965657683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9982828811 + 9982828812.

It is an arithmetic number, because the mean of its divisors is an integer number (9982828812).

Almost surely, 2^19965657623 is an apocalyptic number.

19965657623 is a deficient number, since it is larger than the sum of its proper divisors (1).

19965657623 is an equidigital number, since it uses as much as digits as its factorization.

19965657623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18370800, while the sum is 59.

The spelling of 19965657623 in words is "nineteen billion, nine hundred sixty-five million, six hundred fifty-seven thousand, six hundred twenty-three".