1981278 has 24 divisors (see below), whose sum is σ = 4623528. Its totient is φ = 609552.

The previous prime is 1981277. The next prime is 1981297. The reversal of 1981278 is 8721891.

It is a super-3 number, since 3×1981278³ = 23332297552182890856, which contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981277) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4000 + ... + 4467.

It is an arithmetic number, because the mean of its divisors is an integer number (192647).

2^1981278 is an apocalyptic number.

1981278 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1981278 is an abundant number, since it is smaller than the sum of its proper divisors (2642250).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1981278 is a wasteful number, since it uses less digits than its factorization.

1981278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8488 (or 8485 counting only the distinct ones).

The product of its digits is 8064, while the sum is 36.

The square root of 1981278 is about 1407.5787722185. The cubic root of 1981278 is about 125.5977344852.

It can be divided in two parts, 198127 and 8, that added together give a triangular number (198135 = T₆₂₉).

The spelling of 1981278 in words is "one million, nine hundred eighty-one thousand, two hundred seventy-eight".