1638564802249 has 2 divisors, whose sum is σ = 1638564802250. Its totient is φ = 1638564802248.

The previous prime is 1638564802247. The next prime is 1638564802271. The reversal of 1638564802249 is 9422084658361.

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., 1223165217024 + 415399585225 = 1105968^2 + 644515^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638564802249 - 2¹ = 1638564802247 is a prime.

It is a super-2 number, since 2×1638564802249² (a number of 25 digits) contains 22 as substring.

Together with 1638564802247, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 1638564802193 and 1638564802202.

It is not a weakly prime, because it can be changed into another prime (1638564802247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819282401124 + 819282401125.

It is an arithmetic number, because the mean of its divisors is an integer number (819282401125).

Almost surely, 2^{1638564802249} is an apocalyptic number.

It is an amenable number.

1638564802249 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638564802249 is an equidigital number, since it uses as much as digits as its factorization.

1638564802249 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19906560, while the sum is 58.

The spelling of 1638564802249 in words is "one trillion, six hundred thirty-eight billion, five hundred sixty-four million, eight hundred two thousand, two hundred forty-nine".