1638752191393 has 4 divisors (see below), whose sum is σ = 1735149379140. Its totient is φ = 1542355003648.

The previous prime is 1638752191367. The next prime is 1638752191469. The reversal of 1638752191393 is 3931912578361.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1068231803809 + 570520387584 = 1033553^2 + 755328^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638752191393 - 2¹⁷ = 1638752060321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1638752191333) 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, 48198593848 + ... + 48198593881.

It is an arithmetic number, because the mean of its divisors is an integer number (433787344785).

Almost surely, 2^{1638752191393} is an apocalyptic number.

It is an amenable number.

1638752191393 is a deficient number, since it is larger than the sum of its proper divisors (96397187747).

1638752191393 is an equidigital number, since it uses as much as digits as its factorization.

1638752191393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96397187746.

The product of its digits is 7348320, while the sum is 58.

The spelling of 1638752191393 in words is "one trillion, six hundred thirty-eight billion, seven hundred fifty-two million, one hundred ninety-one thousand, three hundred ninety-three".