1991700020806 has 16 divisors (see below), whose sum is σ = 2990950531200. Its totient is φ = 994716644608.

The previous prime is 1991700020773. The next prime is 1991700020831. The reversal of 1991700020806 is 6080200071991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52597776 + ... + 52635628.

It is an arithmetic number, because the mean of its divisors is an integer number (186934408200).

Almost surely, 2^{1991700020806} is an apocalyptic number.

1991700020806 is a deficient number, since it is larger than the sum of its proper divisors (999250510394).

1991700020806 is a wasteful number, since it uses less digits than its factorization.

1991700020806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67103.

The product of its (nonzero) digits is 54432, while the sum is 43.

The spelling of 1991700020806 in words is "one trillion, nine hundred ninety-one billion, seven hundred million, twenty thousand, eight hundred six".