1983128381 has 4 divisors (see below), whose sum is σ = 2135676732. Its totient is φ = 1830580032.

The previous prime is 1983128369. The next prime is 1983128437. The reversal of 1983128381 is 1838213891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 692163481 + 1290964900 = 26309^2 + 35930^2 .

It is a cyclic number.

It is not a de Polignac number, because 1983128381 - 2¹⁰ = 1983127357 is a prime.

It is a super-2 number, since 2×1983128381² = 7865596351055362322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1983128341) 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, 76274156 + ... + 76274181.

It is an arithmetic number, because the mean of its divisors is an integer number (533919183).

Almost surely, 2^1983128381 is an apocalyptic number.

It is an amenable number.

1983128381 is a deficient number, since it is larger than the sum of its proper divisors (152548351).

1983128381 is a wasteful number, since it uses less digits than its factorization.

1983128381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152548350.

The product of its digits is 82944, while the sum is 44.

The square root of 1983128381 is about 44532.3296156848. The cubic root of 1983128381 is about 1256.3682227758.

The spelling of 1983128381 in words is "one billion, nine hundred eighty-three million, one hundred twenty-eight thousand, three hundred eighty-one".