20845861 has 4 divisors (see below), whose sum is σ = 21048352. Its totient is φ = 20643372.

The previous prime is 20845849. The next prime is 20845871. The reversal of 20845861 is 16854802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16854802 = 2 ⋅8427401.

It is a cyclic number.

It is not a de Polignac number, because 20845861 - 2¹¹ = 20843813 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 (20845871) 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, 101091 + ... + 101296.

It is an arithmetic number, because the mean of its divisors is an integer number (5262088).

Almost surely, 2^20845861 is an apocalyptic number.

It is an amenable number.

20845861 is a deficient number, since it is larger than the sum of its proper divisors (202491).

20845861 is a wasteful number, since it uses less digits than its factorization.

20845861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202490.

The product of its (nonzero) digits is 15360, while the sum is 34.

The square root of 20845861 is about 4565.7267767575. The cubic root of 20845861 is about 275.2157469483.

The spelling of 20845861 in words is "twenty million, eight hundred forty-five thousand, eight hundred sixty-one".