20643269 has 2 divisors, whose sum is σ = 20643270. Its totient is φ = 20643268.

The previous prime is 20643257. The next prime is 20643313. The reversal of 20643269 is 96234602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20205025 + 438244 = 4495^2 + 662^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20643269 is a prime.

It is a super-2 number, since 2×20643269² = 852289110012722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20643229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10321634 + 10321635.

It is an arithmetic number, because the mean of its divisors is an integer number (10321635).

Almost surely, 2^20643269 is an apocalyptic number.

It is an amenable number.

20643269 is a deficient number, since it is larger than the sum of its proper divisors (1).

20643269 is an equidigital number, since it uses as much as digits as its factorization.

20643269 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 20643269 is about 4543.4864366475. The cubic root of 20643269 is about 274.3212749834.

The spelling of 20643269 in words is "twenty million, six hundred forty-three thousand, two hundred sixty-nine".