19941643 has 2 divisors, whose sum is σ = 19941644. Its totient is φ = 19941642.

The previous prime is 19941641. The next prime is 19941653. The reversal of 19941643 is 34614991.

It is a weak prime.

It is an emirp because it is prime and its reverse (34614991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19941643 - 2¹ = 19941641 is a prime.

Together with 19941641, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (19941641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9970821 + 9970822.

It is an arithmetic number, because the mean of its divisors is an integer number (9970822).

Almost surely, 2^19941643 is an apocalyptic number.

19941643 is a deficient number, since it is larger than the sum of its proper divisors (1).

19941643 is an equidigital number, since it uses as much as digits as its factorization.

19941643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 37.

The square root of 19941643 is about 4465.6066777091. The cubic root of 19941643 is about 271.1774956817.

The spelling of 19941643 in words is "nineteen million, nine hundred forty-one thousand, six hundred forty-three".