20643353 has 2 divisors, whose sum is σ = 20643354. Its totient is φ = 20643352.

The previous prime is 20643347. The next prime is 20643379. The reversal of 20643353 is 35334602.

It is an a-pointer prime, because the next prime (20643379) can be obtained adding 20643353 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20539024 + 104329 = 4532^2 + 323^2 .

It is a cyclic number.

It is not a de Polignac number, because 20643353 - 2²² = 16449049 is a prime.

It is a super-2 number, since 2×20643353² = 852296046165218, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20643313) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10321676 + 10321677.

It is an arithmetic number, because the mean of its divisors is an integer number (10321677).

Almost surely, 2^20643353 is an apocalyptic number.

It is an amenable number.

20643353 is a deficient number, since it is larger than the sum of its proper divisors (1).

20643353 is an equidigital number, since it uses as much as digits as its factorization.

20643353 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 26.

The square root of 20643353 is about 4543.4956806406. The cubic root of 20643353 is about 274.3216470652.

Adding to 20643353 its reverse (35334602), we get a palindrome (55977955).

The spelling of 20643353 in words is "twenty million, six hundred forty-three thousand, three hundred fifty-three".