10001820 has 48 divisors (see below), whose sum is σ = 28334880. Its totient is φ = 2635776.

The previous prime is 10001819. The next prime is 10001821. The reversal of 10001820 is 2810001.

It is a happy number.

10001820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (10001819) and next prime (10001821).

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

It is a junction number, because it is equal to n+sod(n) for n = 10001796 and 10001805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10001821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4404 + ... + 6276.

It is an arithmetic number, because the mean of its divisors is an integer number (590310).

Almost surely, 2^10001820 is an apocalyptic number.

10001820 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 10001820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14167440).

10001820 is an abundant number, since it is smaller than the sum of its proper divisors (18333060).

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

10001820 is a wasteful number, since it uses less digits than its factorization.

10001820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1974 (or 1972 counting only the distinct ones).

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

The square root of 10001820 is about 3162.5654143432. The cubic root of 10001820 is about 215.4565384475.

Adding to 10001820 its reverse (2810001), we get a palindrome (12811821).

The spelling of 10001820 in words is "ten million, one thousand, eight hundred twenty".