1993553991 has 64 divisors (see below), whose sum is σ = 3506173440. Its totient is φ = 1103569920.

The previous prime is 1993553963. The next prime is 1993554037.

1993553991 is a `hidden beast` number, since 19 + 9 + 3 + 5 + 539 + 91 = 666.

1993553991 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1993553991 - 2⁵ = 1993553959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1993553591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 371856 + ... + 377178.

It is an arithmetic number, because the mean of its divisors is an integer number (54783960).

Almost surely, 2^1993553991 is an apocalyptic number.

1993553991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1993553991 is a deficient number, since it is larger than the sum of its proper divisors (1512619449).

1993553991 is a wasteful number, since it uses less digits than its factorization.

1993553991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5453 (or 5447 counting only the distinct ones).

The product of its digits is 1476225, while the sum is 54.

The square root of 1993553991 is about 44649.2328153575. The cubic root of 1993553991 is about 1258.5660160193.

The spelling of 1993553991 in words is "one billion, nine hundred ninety-three million, five hundred fifty-three thousand, nine hundred ninety-one".