1983311981 has 4 divisors (see below), whose sum is σ = 2266642272. Its totient is φ = 1699981692.

The previous prime is 1983311947. The next prime is 1983312043. The reversal of 1983311981 is 1891133891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1983311981 - 2⁶ = 1983311917 is a prime.

It is a super-2 number, since 2×1983311981² = 7867052827956288722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1983310981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141665135 + ... + 141665148.

It is an arithmetic number, because the mean of its divisors is an integer number (566660568).

Almost surely, 2^1983311981 is an apocalyptic number.

It is an amenable number.

1983311981 is a deficient number, since it is larger than the sum of its proper divisors (283330291).

1983311981 is an equidigital number, since it uses as much as digits as its factorization.

1983311981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283330290.

The product of its digits is 46656, while the sum is 44.

The square root of 1983311981 is about 44534.3909916819. The cubic root of 1983311981 is about 1256.4069935196.

The spelling of 1983311981 in words is "one billion, nine hundred eighty-three million, three hundred eleven thousand, nine hundred eighty-one".