19996649 has 2 divisors, whose sum is σ = 19996650. Its totient is φ = 19996648.

The previous prime is 19996621. The next prime is 19996651. The reversal of 19996649 is 94669991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19642624 + 354025 = 4432^2 + 595^2 .

It is a cyclic number.

It is not a de Polignac number, because 19996649 - 2⁸ = 19996393 is a prime.

Together with 19996651, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19996649.

It is not a weakly prime, because it can be changed into another prime (19996049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9998324 + 9998325.

It is an arithmetic number, because the mean of its divisors is an integer number (9998325).

Almost surely, 2^19996649 is an apocalyptic number.

It is an amenable number.

19996649 is a deficient number, since it is larger than the sum of its proper divisors (1).

19996649 is an equidigital number, since it uses as much as digits as its factorization.

19996649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 944784, while the sum is 53.

The square root of 19996649 is about 4471.7612861153. The cubic root of 19996649 is about 271.4266007903.

The spelling of 19996649 in words is "nineteen million, nine hundred ninety-six thousand, six hundred forty-nine".