1981000 has 64 divisors (see below), whose sum is σ = 5316480. Its totient is φ = 676800.

The previous prime is 1980991. The next prime is 1981037. The reversal of 1981000 is 1891.

It is a super-2 number, since 2×1981000² = 7848722000000, which contains 22 as substring.

It is a plaindrome in base 11.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6859 + ... + 7141.

It is an arithmetic number, because the mean of its divisors is an integer number (83070).

2^1981000 is an apocalyptic number.

1981000 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 1981000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2658240).

1981000 is an abundant number, since it is smaller than the sum of its proper divisors (3335480).

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

1981000 is a wasteful number, since it uses less digits than its factorization.

1981000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311 (or 297 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 1981000 is about 1407.4800176201. The cubic root of 1981000 is about 125.5918598589.

Adding to 1981000 its reverse (1891), we get a palindrome (1982891).

The spelling of 1981000 in words is "one million, nine hundred eighty-one thousand".