20641679 has 2 divisors, whose sum is σ = 20641680. Its totient is φ = 20641678.

The previous prime is 20641669. The next prime is 20641717. The reversal of 20641679 is 97614602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20641679 - 2¹² = 20637583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20641609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10320839 + 10320840.

It is an arithmetic number, because the mean of its divisors is an integer number (10320840).

Almost surely, 2^20641679 is an apocalyptic number.

20641679 is a deficient number, since it is larger than the sum of its proper divisors (1).

20641679 is an equidigital number, since it uses as much as digits as its factorization.

20641679 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 20641679 is about 4543.3114575164. The cubic root of 20641679 is about 274.3142318155.

The spelling of 20641679 in words is "twenty million, six hundred forty-one thousand, six hundred seventy-nine".