20570989 has 2 divisors, whose sum is σ = 20570990. Its totient is φ = 20570988.

The previous prime is 20570959. The next prime is 20571013. The reversal of 20570989 is 98907502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19873764 + 697225 = 4458^2 + 835^2 .

It is a cyclic number.

It is not a de Polignac number, because 20570989 - 2⁷ = 20570861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20570909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10285494 + 10285495.

It is an arithmetic number, because the mean of its divisors is an integer number (10285495).

Almost surely, 2^20570989 is an apocalyptic number.

It is an amenable number.

20570989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20570989 is an equidigital number, since it uses as much as digits as its factorization.

20570989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 45360, while the sum is 40.

The square root of 20570989 is about 4535.5252176567. The cubic root of 20570989 is about 274.0007325890. Note that the first 3 decimals are identical.

The spelling of 20570989 in words is "twenty million, five hundred seventy thousand, nine hundred eighty-nine".