1991459363964 has 144 divisors (see below), whose sum is σ = 5580880542720. Its totient is φ = 550523070720.

The previous prime is 1991459363947. The next prime is 1991459363987. The reversal of 1991459363964 is 4693639541991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 138106347 + ... + 138120765.

It is an arithmetic number, because the mean of its divisors is an integer number (38756114880).

Almost surely, 2^{1991459363964} is an apocalyptic number.

1991459363964 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991459363964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2790440271360).

1991459363964 is an abundant number, since it is smaller than the sum of its proper divisors (3589421178756).

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

1991459363964 is a wasteful number, since it uses less digits than its factorization.

1991459363964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22048 (or 22039 counting only the distinct ones).

The product of its digits is 170061120, while the sum is 69.

The spelling of 1991459363964 in words is "one trillion, nine hundred ninety-one billion, four hundred fifty-nine million, three hundred sixty-three thousand, nine hundred sixty-four".