20840887 has 2 divisors, whose sum is σ = 20840888. Its totient is φ = 20840886.

The previous prime is 20840873. The next prime is 20840923. The reversal of 20840887 is 78804802.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20840887 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20840837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10420443 + 10420444.

It is an arithmetic number, because the mean of its divisors is an integer number (10420444).

Almost surely, 2^20840887 is an apocalyptic number.

20840887 is a deficient number, since it is larger than the sum of its proper divisors (1).

20840887 is an equidigital number, since it uses as much as digits as its factorization.

20840887 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28672, while the sum is 37.

The square root of 20840887 is about 4565.1820336105. The cubic root of 20840887 is about 275.1938555999.

The spelling of 20840887 in words is "twenty million, eight hundred forty thousand, eight hundred eighty-seven".