1987553084991 has 4 divisors (see below), whose sum is σ = 2650070779992. Its totient is φ = 1325035389992.

The previous prime is 1987553084977. The next prime is 1987553085043. The reversal of 1987553084991 is 1994803557891.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1987553084991 - 2⁶ = 1987553084927 is a prime.

It is a super-3 number, since 3×1987553084991³ (a number of 38 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987553084921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 331258847496 + ... + 331258847501.

It is an arithmetic number, because the mean of its divisors is an integer number (662517694998).

Almost surely, 2^{1987553084991} is an apocalyptic number.

1987553084991 is a deficient number, since it is larger than the sum of its proper divisors (662517695001).

1987553084991 is an equidigital number, since it uses as much as digits as its factorization.

1987553084991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662517695000.

The product of its (nonzero) digits is 97977600, while the sum is 69.

The spelling of 1987553084991 in words is "one trillion, nine hundred eighty-seven billion, five hundred fifty-three million, eighty-four thousand, nine hundred ninety-one".