20823643 has 2 divisors, whose sum is σ = 20823644. Its totient is φ = 20823642.

The previous prime is 20823619. The next prime is 20823683. The reversal of 20823643 is 34632802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20823643 - 2¹³ = 20815451 is a prime.

It is not a weakly prime, because it can be changed into another prime (20823683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10411821 + 10411822.

It is an arithmetic number, because the mean of its divisors is an integer number (10411822).

Almost surely, 2^20823643 is an apocalyptic number.

20823643 is a deficient number, since it is larger than the sum of its proper divisors (1).

20823643 is an equidigital number, since it uses as much as digits as its factorization.

20823643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 20823643 is about 4563.2929995783. The cubic root of 20823643 is about 275.1179350907.

The spelling of 20823643 in words is "twenty million, eight hundred twenty-three thousand, six hundred forty-three".