20388779 has 2 divisors, whose sum is σ = 20388780. Its totient is φ = 20388778.

The previous prime is 20388773. The next prime is 20388803. The reversal of 20388779 is 97788302.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20388779 - 2²⁴ = 3611563 is a prime.

It is a super-2 number, since 2×20388779² = 831404618221682, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20388773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10194389 + 10194390.

It is an arithmetic number, because the mean of its divisors is an integer number (10194390).

Almost surely, 2^20388779 is an apocalyptic number.

20388779 is a deficient number, since it is larger than the sum of its proper divisors (1).

20388779 is an equidigital number, since it uses as much as digits as its factorization.

20388779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 169344, while the sum is 44.

The square root of 20388779 is about 4515.3935598129. The cubic root of 20388779 is about 273.1893340588.

The spelling of 20388779 in words is "twenty million, three hundred eighty-eight thousand, seven hundred seventy-nine".