20985043 has 4 divisors (see below), whose sum is σ = 21220920. Its totient is φ = 20749168.

The previous prime is 20985017. The next prime is 20985049. The reversal of 20985043 is 34058902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34058902 = 2 ⋅17029451.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20985043 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20984996 and 20985014.

It is not an unprimeable number, because it can be changed into a prime (20985049) 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, 117805 + ... + 117982.

It is an arithmetic number, because the mean of its divisors is an integer number (5305230).

Almost surely, 2^20985043 is an apocalyptic number.

20985043 is a deficient number, since it is larger than the sum of its proper divisors (235877).

20985043 is an equidigital number, since it uses as much as digits as its factorization.

20985043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235876.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 20985043 is about 4580.9434617773. The cubic root of 20985043 is about 275.8269017180.

The spelling of 20985043 in words is "twenty million, nine hundred eighty-five thousand, forty-three".