1021800 has 96 divisors (see below), whose sum is σ = 3437280. Its totient is φ = 249600.

The previous prime is 1021799. The next prime is 1021807. The reversal of 1021800 is 81201.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (1021807) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7735 + ... + 7865.

It is an arithmetic number, because the mean of its divisors is an integer number (35805).

2^1021800 is an apocalyptic number.

1021800 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 1021800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1718640).

1021800 is an abundant number, since it is smaller than the sum of its proper divisors (2415480).

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

1021800 is a wasteful number, since it uses less digits than its factorization.

1021800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1021800 is about 1010.8412338246. The cubic root of 1021800 is about 100.7214492594.

The spelling of 1021800 in words is "one million, twenty-one thousand, eight hundred".