1991693372 has 12 divisors (see below), whose sum is σ = 3637005456. Its totient is φ = 952548960.

The previous prime is 1991693369. The next prime is 1991693381. The reversal of 1991693372 is 2733961991.

It is a self number, because there is not a number n which added to its sum of digits gives 1991693372.

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, 10824329 + ... + 10824512.

It is an arithmetic number, because the mean of its divisors is an integer number (303083788).

Almost surely, 2^1991693372 is an apocalyptic number.

It is an amenable number.

1991693372 is a deficient number, since it is larger than the sum of its proper divisors (1645312084).

1991693372 is a wasteful number, since it uses less digits than its factorization.

1991693372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21648868 (or 21648866 counting only the distinct ones).

The product of its digits is 551124, while the sum is 50.

The square root of 1991693372 is about 44628.3919943347. The cubic root of 1991693372 is about 1258.1743468778.

The spelling of 1991693372 in words is "one billion, nine hundred ninety-one million, six hundred ninety-three thousand, three hundred seventy-two".