1991846774399 has 8 divisors (see below), whose sum is σ = 2060783875920. Its totient is φ = 1922926521600.

The previous prime is 1991846774353. The next prime is 1991846774417. The reversal of 1991846774399 is 9934776481991.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1991846774399 - 2⁸ = 1991846774143 is a prime.

It is a super-2 number, since 2×1991846774399² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991846774329) 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, 3971417 + ... + 4444754.

It is an arithmetic number, because the mean of its divisors is an integer number (257597984490).

Almost surely, 2^{1991846774399} is an apocalyptic number.

1991846774399 is a deficient number, since it is larger than the sum of its proper divisors (68937101521).

1991846774399 is an equidigital number, since it uses as much as digits as its factorization.

1991846774399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8424361.

The product of its digits is 740710656, while the sum is 77.

The spelling of 1991846774399 in words is "one trillion, nine hundred ninety-one billion, eight hundred forty-six million, seven hundred seventy-four thousand, three hundred ninety-nine".