20007643 has 2 divisors, whose sum is σ = 20007644. Its totient is φ = 20007642.

The previous prime is 20007601. The next prime is 20007661. The reversal of 20007643 is 34670002.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20007643 is a prime.

It is not a weakly prime, because it can be changed into another prime (20007683) 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, 10003821 + 10003822.

It is an arithmetic number, because the mean of its divisors is an integer number (10003822).

Almost surely, 2^20007643 is an apocalyptic number.

20007643 is a deficient number, since it is larger than the sum of its proper divisors (1).

20007643 is an equidigital number, since it uses as much as digits as its factorization.

20007643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 20007643 is about 4472.9903867547. The cubic root of 20007643 is about 271.4763344123.

Adding to 20007643 its reverse (34670002), we get a palindrome (54677645).

The spelling of 20007643 in words is "twenty million, seven thousand, six hundred forty-three".