9919785647 has 2 divisors, whose sum is σ = 9919785648. Its totient is φ = 9919785646.

The previous prime is 9919785619. The next prime is 9919785721. The reversal of 9919785647 is 7465879199.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9919785647 - 2¹² = 9919781551 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9919785247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4959892823 + 4959892824.

It is an arithmetic number, because the mean of its divisors is an integer number (4959892824).

Almost surely, 2^9919785647 is an apocalyptic number.

9919785647 is a deficient number, since it is larger than the sum of its proper divisors (1).

9919785647 is an equidigital number, since it uses as much as digits as its factorization.

9919785647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34292160, while the sum is 65.

The square root of 9919785647 is about 99598.1207001417. The cubic root of 9919785647 is about 2148.6586655644.

The spelling of 9919785647 in words is "nine billion, nine hundred nineteen million, seven hundred eighty-five thousand, six hundred forty-seven".