20975643 has 24 divisors (see below), whose sum is σ = 33174960. Its totient is φ = 12692160.

The previous prime is 20975627. The next prime is 20975657. The reversal of 20975643 is 34657902.

20975643 is a `hidden beast` number, since 2 + 0 + 9 + 7 + 5 + 643 = 666.

It is not a de Polignac number, because 20975643 - 2⁴ = 20975627 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20975598 and 20975607.

It is not an unprimeable number, because it can be changed into a prime (20975663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5668 + ... + 8606.

It is an arithmetic number, because the mean of its divisors is an integer number (1382290).

Almost surely, 2^20975643 is an apocalyptic number.

20975643 is a deficient number, since it is larger than the sum of its proper divisors (12199317).

20975643 is a wasteful number, since it uses less digits than its factorization.

20975643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3019 (or 3016 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

The square root of 20975643 is about 4579.9173573330. The cubic root of 20975643 is about 275.7857111089.

The spelling of 20975643 in words is "twenty million, nine hundred seventy-five thousand, six hundred forty-three".