2191804236438 has 16 divisors (see below), whose sum is σ = 4383702596016. Its totient is φ = 730585724960.

The previous prime is 2191804236437. The next prime is 2191804236449. The reversal of 2191804236438 is 8346324081912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191804236437) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3617253 + ... + 4179488.

It is an arithmetic number, because the mean of its divisors is an integer number (273981412251).

Almost surely, 2^{2191804236438} is an apocalyptic number.

2191804236438 is an abundant number, since it is smaller than the sum of its proper divisors (2191898359578).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2191804236438 is a wasteful number, since it uses less digits than its factorization.

2191804236438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7843599.

The product of its (nonzero) digits is 1990656, while the sum is 51.

It can be divided in two parts, 2191804 and 236438, that added together give a palindrome (2428242).

The spelling of 2191804236438 in words is "two trillion, one hundred ninety-one billion, eight hundred four million, two hundred thirty-six thousand, four hundred thirty-eight".