1991849562599 has 4 divisors (see below), whose sum is σ = 2145068759736. Its totient is φ = 1838630365464.

The previous prime is 1991849562553. The next prime is 1991849562617. The reversal of 1991849562599 is 9952659481991.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1991849562599 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 (1991849562509) 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, 76609598549 + ... + 76609598574.

It is an arithmetic number, because the mean of its divisors is an integer number (536267189934).

Almost surely, 2^{1991849562599} is an apocalyptic number.

1991849562599 is a deficient number, since it is larger than the sum of its proper divisors (153219197137).

1991849562599 is a wasteful number, since it uses less digits than its factorization.

1991849562599 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153219197136.

The product of its digits is 566870400, while the sum is 77.

The spelling of 1991849562599 in words is "one trillion, nine hundred ninety-one billion, eight hundred forty-nine million, five hundred sixty-two thousand, five hundred ninety-nine".