1981337885 has 4 divisors (see below), whose sum is σ = 2377605468. Its totient is φ = 1585070304.

The previous prime is 1981337881. The next prime is 1981337887. The reversal of 1981337885 is 5887331891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5887331891 = 7 ⋅841047413.

It can be written as a sum of positive squares in 2 ways, for example, as 1493899801 + 487438084 = 38651^2 + 22078^2 .

It is a cyclic number.

It is not a de Polignac number, because 1981337885 - 2² = 1981337881 is a prime.

It is a super-3 number, since 3×1981337885³ (a number of 29 digits) contains 333 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 (1981337881) 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, 198133784 + ... + 198133793.

It is an arithmetic number, because the mean of its divisors is an integer number (594401367).

Almost surely, 2^1981337885 is an apocalyptic number.

It is an amenable number.

1981337885 is a deficient number, since it is larger than the sum of its proper divisors (396267583).

1981337885 is an equidigital number, since it uses as much as digits as its factorization.

1981337885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396267582.

The product of its digits is 1451520, while the sum is 53.

The square root of 1981337885 is about 44512.2217486389. The cubic root of 1981337885 is about 1255.9899988808.

The spelling of 1981337885 in words is "one billion, nine hundred eighty-one million, three hundred thirty-seven thousand, eight hundred eighty-five".