20953643 has 2 divisors, whose sum is σ = 20953644. Its totient is φ = 20953642.

The previous prime is 20953633. The next prime is 20953663. The reversal of 20953643 is 34635902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20953643 - 2⁶ = 20953579 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20953633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10476821 + 10476822.

It is an arithmetic number, because the mean of its divisors is an integer number (10476822).

Almost surely, 2^20953643 is an apocalyptic number.

20953643 is a deficient number, since it is larger than the sum of its proper divisors (1).

20953643 is an equidigital number, since it uses as much as digits as its factorization.

20953643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 32.

The square root of 20953643 is about 4577.5149371684. The cubic root of 20953643 is about 275.6892594280.

The spelling of 20953643 in words is "twenty million, nine hundred fifty-three thousand, six hundred forty-three".