2805993981 has 80 divisors (see below), whose sum is σ = 4885116544. Its totient is φ = 1572120576.

The previous prime is 2805993947. The next prime is 2805993991. The reversal of 2805993981 is 1893995082.

It is not a de Polignac number, because 2805993981 - 2¹⁰ = 2805992957 is a prime.

It is a super-2 number, since 2×2805993981² = 15747204442816456722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2805993941) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 8964681 + ... + 8964993.

Almost surely, 2^2805993981 is an apocalyptic number.

2805993981 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2805993981 is a deficient number, since it is larger than the sum of its proper divisors (2079122563).

2805993981 is a wasteful number, since it uses less digits than its factorization.

2805993981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 592 (or 583 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 54.

The square root of 2805993981 is about 52971.6337392005. The cubic root of 2805993981 is about 1410.4647766119.

The spelling of 2805993981 in words is "two billion, eight hundred five million, nine hundred ninety-three thousand, nine hundred eighty-one".