20905069 has 2 divisors, whose sum is σ = 20905070. Its totient is φ = 20905068.

The previous prime is 20905061. The next prime is 20905097. The reversal of 20905069 is 96050902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20820969 + 84100 = 4563^2 + 290^2 .

It is a cyclic number.

It is not a de Polignac number, because 20905069 - 2³ = 20905061 is a prime.

It is a super-2 number, since 2×20905069² = 874043819789522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20905069.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20905061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10452534 + 10452535.

It is an arithmetic number, because the mean of its divisors is an integer number (10452535).

Almost surely, 2^20905069 is an apocalyptic number.

It is an amenable number.

20905069 is a deficient number, since it is larger than the sum of its proper divisors (1).

20905069 is an equidigital number, since it uses as much as digits as its factorization.

20905069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4860, while the sum is 31.

The square root of 20905069 is about 4572.2061414595. The cubic root of 20905069 is about 275.4760635460.

The spelling of 20905069 in words is "twenty million, nine hundred five thousand, sixty-nine".