1981980 has 216 divisors, whose sum is σ = 8133216. Its totient is φ = 380160.

The previous prime is 1981963. The next prime is 1981997. The reversal of 1981980 is 891891.

It is an interprime number because it is at equal distance from previous prime (1981963) and next prime (1981997).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 152454 + ... + 152466.

2^1981980 is an apocalyptic number.

1981980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1981980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4066608).

1981980 is an abundant number, since it is smaller than the sum of its proper divisors (6151236).

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

1981980 is a wasteful number, since it uses less digits than its factorization.

1981980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 1981980 is about 1407.8281145083. The cubic root of 1981980 is about 125.6125665277.

1981980 divided by its sum of digits (36) gives a palindrome (55055).

The spelling of 1981980 in words is "one million, nine hundred eighty-one thousand, nine hundred eighty".