20647769 has 2 divisors, whose sum is σ = 20647770. Its totient is φ = 20647768.

The previous prime is 20647763. The next prime is 20647777. The reversal of 20647769 is 96774602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11424400 + 9223369 = 3380^2 + 3037^2 .

It is a cyclic number.

It is not a de Polignac number, because 20647769 - 2⁸ = 20647513 is a prime.

It is a super-2 number, since 2×20647769² = 852660729354722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20647763) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10323884 + 10323885.

It is an arithmetic number, because the mean of its divisors is an integer number (10323885).

Almost surely, 2^20647769 is an apocalyptic number.

It is an amenable number.

20647769 is a deficient number, since it is larger than the sum of its proper divisors (1).

20647769 is an equidigital number, since it uses as much as digits as its factorization.

20647769 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 127008, while the sum is 41.

The square root of 20647769 is about 4543.9816240826. The cubic root of 20647769 is about 274.3412065173.

The spelling of 20647769 in words is "twenty million, six hundred forty-seven thousand, seven hundred sixty-nine".