1639439785969 has 2 divisors, whose sum is σ = 1639439785970. Its totient is φ = 1639439785968.

The previous prime is 1639439785967. The next prime is 1639439786009. The reversal of 1639439785969 is 9695879349361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1470447264400 + 168992521569 = 1212620^2 + 411087^2 .

It is a cyclic number.

It is not a de Polignac number, because 1639439785969 - 2¹ = 1639439785967 is a prime.

It is a super-2 number, since 2×1639439785969² (a number of 25 digits) contains 22 as substring.

Together with 1639439785967, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1639439785967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819719892984 + 819719892985.

It is an arithmetic number, because the mean of its divisors is an integer number (819719892985).

Almost surely, 2^{1639439785969} is an apocalyptic number.

It is an amenable number.

1639439785969 is a deficient number, since it is larger than the sum of its proper divisors (1).

1639439785969 is an equidigital number, since it uses as much as digits as its factorization.

1639439785969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2380855680, while the sum is 79.

The spelling of 1639439785969 in words is "one trillion, six hundred thirty-nine billion, four hundred thirty-nine million, seven hundred eighty-five thousand, nine hundred sixty-nine".