20344646543657 has 2 divisors, whose sum is σ = 20344646543658. Its totient is φ = 20344646543656.

The previous prime is 20344646543531. The next prime is 20344646543659. The reversal of 20344646543657 is 75634564644302.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11192744949136 + 9151901594521 = 3345556^2 + 3025211^2 .

It is a cyclic number.

It is not a de Polignac number, because 20344646543657 - 2¹⁸ = 20344646281513 is a prime.

Together with 20344646543659, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20344646543596 and 20344646543605.

It is not a weakly prime, because it can be changed into another prime (20344646543659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10172323271828 + 10172323271829.

It is an arithmetic number, because the mean of its divisors is an integer number (10172323271829).

Almost surely, 2^{20344646543657} is an apocalyptic number.

It is an amenable number.

20344646543657 is a deficient number, since it is larger than the sum of its proper divisors (1).

20344646543657 is an equidigital number, since it uses as much as digits as its factorization.

20344646543657 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 174182400, while the sum is 59.

The spelling of 20344646543657 in words is "twenty trillion, three hundred forty-four billion, six hundred forty-six million, five hundred forty-three thousand, six hundred fifty-seven".