20840145 has 16 divisors (see below), whose sum is σ = 33495360. Its totient is φ = 11064384.

The previous prime is 20840123. The next prime is 20840167. The reversal of 20840145 is 54104802.

It is an interprime number because it is at equal distance from previous prime (20840123) and next prime (20840167).

It is not a de Polignac number, because 20840145 - 2¹⁶ = 20774609 is a prime.

It is a Curzon number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 402 + ... + 6468.

It is an arithmetic number, because the mean of its divisors is an integer number (2093460).

Almost surely, 2^20840145 is an apocalyptic number.

It is an amenable number.

20840145 is a deficient number, since it is larger than the sum of its proper divisors (12655215).

20840145 is a wasteful number, since it uses less digits than its factorization.

20840145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6304.

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 20840145 is about 4565.1007655911. The cubic root of 20840145 is about 275.1905896438.

Adding to 20840145 its reverse (54104802), we get a palindrome (74944947).

The spelling of 20840145 in words is "twenty million, eight hundred forty thousand, one hundred forty-five".