1981650 has 48 divisors (see below), whose sum is σ = 5365728. Its totient is φ = 480000.

The previous prime is 1981649. The next prime is 1981663. The reversal of 1981650 is 561891.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1050 + ... + 2250.

It is an arithmetic number, because the mean of its divisors is an integer number (111786).

2^1981650 is an apocalyptic number.

1981650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1981650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2682864).

1981650 is an abundant number, since it is smaller than the sum of its proper divisors (3384078).

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

1981650 is a wasteful number, since it uses less digits than its factorization.

1981650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1227 (or 1222 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 30.

The square root of 1981650 is about 1407.7109078216. The cubic root of 1981650 is about 125.6055946363.

The spelling of 1981650 in words is "one million, nine hundred eighty-one thousand, six hundred fifty".