20641399 has 2 divisors, whose sum is σ = 20641400. Its totient is φ = 20641398.

The previous prime is 20641393. The next prime is 20641403. The reversal of 20641399 is 99314602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20641399 - 2⁹ = 20640887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20641393) 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, 10320699 + 10320700.

It is an arithmetic number, because the mean of its divisors is an integer number (10320700).

Almost surely, 2^20641399 is an apocalyptic number.

20641399 is a deficient number, since it is larger than the sum of its proper divisors (1).

20641399 is an equidigital number, since it uses as much as digits as its factorization.

20641399 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 20641399 is about 4543.2806428835. The cubic root of 20641399 is about 274.3129914718.

The spelling of 20641399 in words is "twenty million, six hundred forty-one thousand, three hundred ninety-nine".