1638619891127 has 2 divisors, whose sum is σ = 1638619891128. Its totient is φ = 1638619891126.

The previous prime is 1638619891109. The next prime is 1638619891151. The reversal of 1638619891127 is 7211989168361.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1638619891127 - 2⁶ = 1638619891063 is a prime.

It is a super-2 number, since 2×1638619891127² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1638619891127.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1638619891157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819309945563 + 819309945564.

It is an arithmetic number, because the mean of its divisors is an integer number (819309945564).

Almost surely, 2^{1638619891127} is an apocalyptic number.

1638619891127 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638619891127 is an equidigital number, since it uses as much as digits as its factorization.

1638619891127 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7838208, while the sum is 62.

The spelling of 1638619891127 in words is "one trillion, six hundred thirty-eight billion, six hundred nineteen million, eight hundred ninety-one thousand, one hundred twenty-seven".