1997796977991 has 72 divisors (see below), whose sum is σ = 3012461612160. Its totient is φ = 1275114778560.

The previous prime is 1997796977987. The next prime is 1997796978029.

1997796977991 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1997796977991 - 2² = 1997796977987 is a prime.

It is a super-3 number, since 3×1997796977991³ (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 (1997796977971) 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 71 ways as a sum of consecutive naturals, for example, 442086030 + ... + 442090548.

Almost surely, 2^{1997796977991} is an apocalyptic number.

1997796977991 is a deficient number, since it is larger than the sum of its proper divisors (1014664634169).

1997796977991 is a wasteful number, since it uses less digits than its factorization.

1997796977991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4997 (or 4933 counting only the distinct ones).

The product of its digits is 7655939046, while the sum is 90.

The spelling of 1997796977991 in words is "one trillion, nine hundred ninety-seven billion, seven hundred ninety-six million, nine hundred seventy-seven thousand, nine hundred ninety-one".