1996556991 has 96 divisors (see below), whose sum is σ = 3281886720. Its totient is φ = 1071840000.

The previous prime is 1996556987. The next prime is 1996557041.

1996556991 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1996556991 - 2² = 1996556987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1996556921) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 19767841 + ... + 19767941.

It is an arithmetic number, because the mean of its divisors is an integer number (34186320).

Almost surely, 2^1996556991 is an apocalyptic number.

1996556991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1996556991 is a deficient number, since it is larger than the sum of its proper divisors (1285329729).

1996556991 is a wasteful number, since it uses less digits than its factorization.

1996556991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269 (or 258 counting only the distinct ones).

The product of its digits is 5904900, while the sum is 60.

The square root of 1996556991 is about 44682.8489579615. The cubic root of 1996556991 is about 1259.1976480371.

The spelling of 1996556991 in words is "one billion, nine hundred ninety-six million, five hundred fifty-six thousand, nine hundred ninety-one".