18191201029391 has 4 divisors (see below), whose sum is σ = 19590524185512. Its totient is φ = 16791877873272.

The previous prime is 18191201029369. The next prime is 18191201029399. The reversal of 18191201029391 is 19392010219181.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 18191201029391 - 2²⁶ = 18191133920527 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 (18191201029399) 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, 699661578041 + ... + 699661578066.

It is an arithmetic number, because the mean of its divisors is an integer number (4897631046378).

Almost surely, 2^{18191201029391} is an apocalyptic number.

18191201029391 is a deficient number, since it is larger than the sum of its proper divisors (1399323156121).

18191201029391 is a wasteful number, since it uses less digits than its factorization.

18191201029391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1399323156120.

The product of its (nonzero) digits is 69984, while the sum is 47.

The spelling of 18191201029391 in words is "eighteen trillion, one hundred ninety-one billion, two hundred one million, twenty-nine thousand, three hundred ninety-one".