20875643 has 4 divisors (see below), whose sum is σ = 22103640. Its totient is φ = 19647648.

The previous prime is 20875637. The next prime is 20875667. The reversal of 20875643 is 34657802.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34657802 = 2 ⋅17328901.

It is not a de Polignac number, because 20875643 - 2⁴ = 20875627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20875343) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 613973 + ... + 614006.

It is an arithmetic number, because the mean of its divisors is an integer number (5525910).

Almost surely, 2^20875643 is an apocalyptic number.

20875643 is a deficient number, since it is larger than the sum of its proper divisors (1227997).

20875643 is a wasteful number, since it uses less digits than its factorization.

20875643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1227996.

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 20875643 is about 4568.9870868717. The cubic root of 20875643 is about 275.3467493744.

The spelling of 20875643 in words is "twenty million, eight hundred seventy-five thousand, six hundred forty-three".