1981240 has 16 divisors (see below), whose sum is σ = 4457880. Its totient is φ = 792480.

The previous prime is 1981237. The next prime is 1981247. The reversal of 1981240 is 421891.

It is a happy number.

It is a super-3 number, since 3×1981240³ = 23330955069751872000, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981247) 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, 24726 + ... + 24805.

2^1981240 is an apocalyptic number.

1981240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1981240 is an abundant number, since it is smaller than the sum of its proper divisors (2476640).

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

1981240 is a wasteful number, since it uses less digits than its factorization.

1981240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49542 (or 49538 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 1981240 is about 1407.5652737973. The cubic root of 1981240 is about 125.5969315112.

The spelling of 1981240 in words is "one million, nine hundred eighty-one thousand, two hundred forty".