20198779 has 2 divisors, whose sum is σ = 20198780. Its totient is φ = 20198778.

The previous prime is 20198753. The next prime is 20198791. The reversal of 20198779 is 97789102.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20198779 - 2²³ = 11810171 is a prime.

It is not a weakly prime, because it can be changed into another prime (20198279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10099389 + 10099390.

It is an arithmetic number, because the mean of its divisors is an integer number (10099390).

Almost surely, 2^20198779 is an apocalyptic number.

20198779 is a deficient number, since it is larger than the sum of its proper divisors (1).

20198779 is an equidigital number, since it uses as much as digits as its factorization.

20198779 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 20198779 is about 4494.3051743290. The cubic root of 20198779 is about 272.3380807279.

The spelling of 20198779 in words is "twenty million, one hundred ninety-eight thousand, seven hundred seventy-nine".