2091867981 has 16 divisors (see below), whose sum is σ = 3191230464. Its totient is φ = 1193994864.

The previous prime is 2091867931. The next prime is 2091867983. The reversal of 2091867981 is 1897681902.

It is not a de Polignac number, because 2091867981 - 2¹⁰ = 2091866957 is a prime.

It is a super-2 number, since 2×2091867981² = 8751823299866032722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2091867983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37525 + ... + 74778.

It is an arithmetic number, because the mean of its divisors is an integer number (199451904).

Almost surely, 2^2091867981 is an apocalyptic number.

2091867981 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2091867981 is a deficient number, since it is larger than the sum of its proper divisors (1099362483).

2091867981 is a wasteful number, since it uses less digits than its factorization.

2091867981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113200.

The product of its (nonzero) digits is 435456, while the sum is 51.

The square root of 2091867981 is about 45736.9432843954. The cubic root of 2091867981 is about 1278.9240594232.

The spelling of 2091867981 in words is "two billion, ninety-one million, eight hundred sixty-seven thousand, nine hundred eighty-one".