1981377843 has 4 divisors (see below), whose sum is σ = 2641837128. Its totient is φ = 1320918560.

The previous prime is 1981377833. The next prime is 1981377847. The reversal of 1981377843 is 3487731891.

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 1981377843 - 2⁹ = 1981377331 is a prime.

It is a super-3 number, since 3×1981377843³ (a number of 29 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (1981377847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 330229638 + ... + 330229643.

It is an arithmetic number, because the mean of its divisors is an integer number (660459282).

Almost surely, 2^1981377843 is an apocalyptic number.

1981377843 is a deficient number, since it is larger than the sum of its proper divisors (660459285).

1981377843 is an equidigital number, since it uses as much as digits as its factorization.

1981377843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660459284.

The product of its digits is 1016064, while the sum is 51.

The square root of 1981377843 is about 44512.6705893951. The cubic root of 1981377843 is about 1255.9984420833.

The spelling of 1981377843 in words is "one billion, nine hundred eighty-one million, three hundred seventy-seven thousand, eight hundred forty-three".