20566979 has 2 divisors, whose sum is σ = 20566980. Its totient is φ = 20566978.

The previous prime is 20566969. The next prime is 20566999. The reversal of 20566979 is 97966502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20566979 - 2⁴ = 20566963 is a prime.

It is not a weakly prime, because it can be changed into another prime (20566969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10283489 + 10283490.

It is an arithmetic number, because the mean of its divisors is an integer number (10283490).

Almost surely, 2^20566979 is an apocalyptic number.

20566979 is a deficient number, since it is larger than the sum of its proper divisors (1).

20566979 is an equidigital number, since it uses as much as digits as its factorization.

20566979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 204120, while the sum is 44.

The square root of 20566979 is about 4535.0831304398. The cubic root of 20566979 is about 273.9829273466.

The spelling of 20566979 in words is "twenty million, five hundred sixty-six thousand, nine hundred seventy-nine".