20640793 has 2 divisors, whose sum is σ = 20640794. Its totient is φ = 20640792.

The previous prime is 20640787. The next prime is 20640827. The reversal of 20640793 is 39704602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10419984 + 10220809 = 3228^2 + 3197^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20640793 is a prime.

It is not a weakly prime, because it can be changed into another prime (20640713) 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, 10320396 + 10320397.

It is an arithmetic number, because the mean of its divisors is an integer number (10320397).

Almost surely, 2^20640793 is an apocalyptic number.

It is an amenable number.

20640793 is a deficient number, since it is larger than the sum of its proper divisors (1).

20640793 is an equidigital number, since it uses as much as digits as its factorization.

20640793 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 31.

The square root of 20640793 is about 4543.2139504980. The cubic root of 20640793 is about 274.3103069751.

The spelling of 20640793 in words is "twenty million, six hundred forty thousand, seven hundred ninety-three".