19640651 has 2 divisors, whose sum is σ = 19640652. Its totient is φ = 19640650.

The previous prime is 19640633. The next prime is 19640653. The reversal of 19640651 is 15604691.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19640651 - 2⁶ = 19640587 is a prime.

Together with 19640653, 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 (19640653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9820325 + 9820326.

It is an arithmetic number, because the mean of its divisors is an integer number (9820326).

Almost surely, 2^19640651 is an apocalyptic number.

19640651 is a deficient number, since it is larger than the sum of its proper divisors (1).

19640651 is an equidigital number, since it uses as much as digits as its factorization.

19640651 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 19640651 is about 4431.7774086703. Note that the first 3 decimals coincide. The cubic root of 19640651 is about 269.8062212694.

The spelling of 19640651 in words is "nineteen million, six hundred forty thousand, six hundred fifty-one".