1991189364 has 12 divisors (see below), whose sum is σ = 4646108544. Its totient is φ = 663729784.

The previous prime is 1991189359. The next prime is 1991189371. The reversal of 1991189364 is 4639811991.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82966212 + ... + 82966235.

It is an arithmetic number, because the mean of its divisors is an integer number (387175712).

Almost surely, 2^1991189364 is an apocalyptic number.

It is an amenable number.

1991189364 is an abundant number, since it is smaller than the sum of its proper divisors (2654919180).

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

1991189364 is a wasteful number, since it uses less digits than its factorization.

1991189364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165932454 (or 165932452 counting only the distinct ones).

The product of its digits is 419904, while the sum is 51.

The square root of 1991189364 is about 44622.7449178107. The cubic root of 1991189364 is about 1258.0682088142.

The spelling of 1991189364 in words is "one billion, nine hundred ninety-one million, one hundred eighty-nine thousand, three hundred sixty-four".