11821020 has 48 divisors (see below), whose sum is σ = 33266688. Its totient is φ = 3136320.

The previous prime is 11820971. The next prime is 11821027. The reversal of 11821020 is 2012811.

11821020 = 524² + 525² + ... + 563².

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11821027) 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, 15897 + ... + 16623.

It is an arithmetic number, because the mean of its divisors is an integer number (693056).

Almost surely, 2^11821020 is an apocalyptic number.

11821020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

11821020 is an abundant number, since it is smaller than the sum of its proper divisors (21445668).

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

11821020 is a wasteful number, since it uses less digits than its factorization.

11821020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1010 (or 1008 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

The square root of 11821020 is about 3438.1710254145. The cubic root of 11821020 is about 227.7989147327.

Adding to 11821020 its reverse (2012811), we get a palindrome (13833831).

The spelling of 11821020 in words is "eleven million, eight hundred twenty-one thousand, twenty".