20280109 has 2 divisors, whose sum is σ = 20280110. Its totient is φ = 20280108.

The previous prime is 20280103. The next prime is 20280119. The reversal of 20280109 is 90108202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19980900 + 299209 = 4470^2 + 547^2 .

It is a cyclic number.

It is not a de Polignac number, because 20280109 - 2³ = 20280101 is a prime.

It is a super-2 number, since 2×20280109² = 822565642103762, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20280109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20280101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10140054 + 10140055.

It is an arithmetic number, because the mean of its divisors is an integer number (10140055).

Almost surely, 2^20280109 is an apocalyptic number.

It is an amenable number.

20280109 is a deficient number, since it is larger than the sum of its proper divisors (1).

20280109 is an equidigital number, since it uses as much as digits as its factorization.

20280109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 20280109 is about 4503.3442018127. The cubic root of 20280109 is about 272.7031126039.

The spelling of 20280109 in words is "twenty million, two hundred eighty thousand, one hundred nine".