20949109 has 2 divisors, whose sum is σ = 20949110. Its totient is φ = 20949108.

The previous prime is 20949101. The next prime is 20949157. The reversal of 20949109 is 90194902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19166884 + 1782225 = 4378^2 + 1335^2 .

It is a cyclic number.

It is not a de Polignac number, because 20949109 - 2³ = 20949101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20949101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10474554 + 10474555.

It is an arithmetic number, because the mean of its divisors is an integer number (10474555).

Almost surely, 2^20949109 is an apocalyptic number.

It is an amenable number.

20949109 is a deficient number, since it is larger than the sum of its proper divisors (1).

20949109 is an equidigital number, since it uses as much as digits as its factorization.

20949109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 20949109 is about 4577.0196634928. The cubic root of 20949109 is about 275.6693732238.

The spelling of 20949109 in words is "twenty million, nine hundred forty-nine thousand, one hundred nine".