19471897649 has 2 divisors, whose sum is σ = 19471897650. Its totient is φ = 19471897648.

The previous prime is 19471897639. The next prime is 19471897651. The reversal of 19471897649 is 94679817491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15733186624 + 3738711025 = 125432^2 + 61145^2 .

It is a cyclic number.

It is not a de Polignac number, because 19471897649 - 2⁴ = 19471897633 is a prime.

Together with 19471897651, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19471897639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9735948824 + 9735948825.

It is an arithmetic number, because the mean of its divisors is an integer number (9735948825).

Almost surely, 2^19471897649 is an apocalyptic number.

It is an amenable number.

19471897649 is a deficient number, since it is larger than the sum of its proper divisors (1).

19471897649 is an equidigital number, since it uses as much as digits as its factorization.

19471897649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27433728, while the sum is 65.

The spelling of 19471897649 in words is "nineteen billion, four hundred seventy-one million, eight hundred ninety-seven thousand, six hundred forty-nine".