20539979 has 2 divisors, whose sum is σ = 20539980. Its totient is φ = 20539978.

The previous prime is 20539963. The next prime is 20539993. The reversal of 20539979 is 97993502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20539979 - 2⁴ = 20539963 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (20539919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10269989 + 10269990.

It is an arithmetic number, because the mean of its divisors is an integer number (10269990).

Almost surely, 2^20539979 is an apocalyptic number.

20539979 is a deficient number, since it is larger than the sum of its proper divisors (1).

20539979 is an equidigital number, since it uses as much as digits as its factorization.

20539979 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 153090, while the sum is 44.

The square root of 20539979 is about 4532.1053606464. The cubic root of 20539979 is about 273.8629813800.

The spelling of 20539979 in words is "twenty million, five hundred thirty-nine thousand, nine hundred seventy-nine".