20871049 has 2 divisors, whose sum is σ = 20871050. Its totient is φ = 20871048.

The previous prime is 20871047. The next prime is 20871077. The reversal of 20871049 is 94017802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13927824 + 6943225 = 3732^2 + 2635^2 .

It is a cyclic number.

It is not a de Polignac number, because 20871049 - 2¹ = 20871047 is a prime.

Together with 20871047, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20871049.

It is not a weakly prime, because it can be changed into another prime (20871043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10435524 + 10435525.

It is an arithmetic number, because the mean of its divisors is an integer number (10435525).

Almost surely, 2^20871049 is an apocalyptic number.

It is an amenable number.

20871049 is a deficient number, since it is larger than the sum of its proper divisors (1).

20871049 is an equidigital number, since it uses as much as digits as its factorization.

20871049 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 20871049 is about 4568.4843219606. The cubic root of 20871049 is about 275.3265498247.

It can be divided in two parts, 2087 and 1049, that added together give a square (3136 = 56²).

The spelling of 20871049 in words is "twenty million, eight hundred seventy-one thousand, forty-nine".