20684647553 has 2 divisors, whose sum is σ = 20684647554. Its totient is φ = 20684647552.

The previous prime is 20684647531. The next prime is 20684647579. The reversal of 20684647553 is 35574648602.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20680453249 + 4194304 = 143807^2 + 2048^2 .

It is a cyclic number.

It is not a de Polignac number, because 20684647553 - 2²⁴ = 20667870337 is a prime.

It is not a weakly prime, because it can be changed into another prime (20684647153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10342323776 + 10342323777.

It is an arithmetic number, because the mean of its divisors is an integer number (10342323777).

Almost surely, 2^20684647553 is an apocalyptic number.

It is an amenable number.

20684647553 is a deficient number, since it is larger than the sum of its proper divisors (1).

20684647553 is an equidigital number, since it uses as much as digits as its factorization.

20684647553 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4838400, while the sum is 50.

The spelling of 20684647553 in words is "twenty billion, six hundred eighty-four million, six hundred forty-seven thousand, five hundred fifty-three".