20865943 has 4 divisors (see below), whose sum is σ = 23846800. Its totient is φ = 17885088.

The previous prime is 20865937. The next prime is 20865967. The reversal of 20865943 is 34956802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20865943 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20865983) 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, 1490418 + ... + 1490431.

It is an arithmetic number, because the mean of its divisors is an integer number (5961700).

Almost surely, 2^20865943 is an apocalyptic number.

20865943 is a deficient number, since it is larger than the sum of its proper divisors (2980857).

20865943 is an equidigital number, since it uses as much as digits as its factorization.

20865943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2980856.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 20865943 is about 4567.9254591116. The cubic root of 20865943 is about 275.3040955625.

The spelling of 20865943 in words is "twenty million, eight hundred sixty-five thousand, nine hundred forty-three".