20189779 has 2 divisors, whose sum is σ = 20189780. Its totient is φ = 20189778.

The previous prime is 20189777. The next prime is 20189789. The reversal of 20189779 is 97798102.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20189779 - 2¹ = 20189777 is a prime.

Together with 20189777, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20189777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10094889 + 10094890.

It is an arithmetic number, because the mean of its divisors is an integer number (10094890).

Almost surely, 2^20189779 is an apocalyptic number.

20189779 is a deficient number, since it is larger than the sum of its proper divisors (1).

20189779 is an equidigital number, since it uses as much as digits as its factorization.

20189779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 63504, while the sum is 43.

The square root of 20189779 is about 4493.3037956497. The cubic root of 20189779 is about 272.2976260243.

The spelling of 20189779 in words is "twenty million, one hundred eighty-nine thousand, seven hundred seventy-nine".