1981285 has 8 divisors (see below), whose sum is σ = 2428416. Its totient is φ = 1551120.

The previous prime is 1981277. The next prime is 1981297. The reversal of 1981285 is 5821891.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1981285 - 2³ = 1981277 is a prime.

It is a super-3 number, since 3×1981285³ = 23332544857194972375, which contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1981285.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3981 + ... + 4450.

It is an arithmetic number, because the mean of its divisors is an integer number (303552).

2^1981285 is an apocalyptic number.

It is an amenable number.

1981285 is a deficient number, since it is larger than the sum of its proper divisors (447131).

1981285 is an equidigital number, since it uses as much as digits as its factorization.

1981285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8483.

The product of its digits is 5760, while the sum is 34.

The square root of 1981285 is about 1407.5812587556. The cubic root of 1981285 is about 125.5978824004.

Subtracting 1981285 from its reverse (5821891), we obtain a triangular number (3840606 = T₂₇₇₁).

The spelling of 1981285 in words is "one million, nine hundred eighty-one thousand, two hundred eighty-five".