1638888890389 has 4 divisors (see below), whose sum is σ = 1640695825024. Its totient is φ = 1637081955756.

The previous prime is 1638888890383. The next prime is 1638888890411. The reversal of 1638888890389 is 9830988888361.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1638888890389 - 2³ = 1638888890381 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638888890381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 903465957 + ... + 903467770.

It is an arithmetic number, because the mean of its divisors is an integer number (410173956256).

Almost surely, 2^{1638888890389} is an apocalyptic number.

It is an amenable number.

1638888890389 is a deficient number, since it is larger than the sum of its proper divisors (1806934635).

1638888890389 is an equidigital number, since it uses as much as digits as its factorization.

1638888890389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1806934634.

The product of its (nonzero) digits is 1146617856, while the sum is 79.

The spelling of 1638888890389 in words is "one trillion, six hundred thirty-eight billion, eight hundred eighty-eight million, eight hundred ninety thousand, three hundred eighty-nine".