20840087 has 2 divisors, whose sum is σ = 20840088. Its totient is φ = 20840086.

The previous prime is 20840063. The next prime is 20840107. The reversal of 20840087 is 78004802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20840087 - 2¹⁴ = 20823703 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 (20840887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10420043 + 10420044.

It is an arithmetic number, because the mean of its divisors is an integer number (10420044).

Almost surely, 2^20840087 is an apocalyptic number.

20840087 is a deficient number, since it is larger than the sum of its proper divisors (1).

20840087 is an equidigital number, since it uses as much as digits as its factorization.

20840087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3584, while the sum is 29.

The square root of 20840087 is about 4565.0944130434. The cubic root of 20840087 is about 275.1903343502.

Adding to 20840087 its reverse (78004802), we get a palindrome (98844889).

The spelling of 20840087 in words is "twenty million, eight hundred forty thousand, eighty-seven".