11556820 has 48 divisors (see below), whose sum is σ = 26744256. Its totient is φ = 4160000.

The previous prime is 11556817. The next prime is 11556823. The reversal of 11556820 is 2865511.

11556820 = 318² + 319² + ... + 405².

11556820 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 (11556817) and next prime (11556823).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11556823) 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, 28620 + ... + 29020.

It is an arithmetic number, because the mean of its divisors is an integer number (557172).

Almost surely, 2^11556820 is an apocalyptic number.

11556820 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 11556820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13372128).

11556820 is an abundant number, since it is smaller than the sum of its proper divisors (15187436).

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

11556820 is a wasteful number, since it uses less digits than its factorization.

11556820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 552 (or 550 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 11556820 is about 3399.5323207759. The cubic root of 11556820 is about 226.0890087178.

The spelling of 11556820 in words is "eleven million, five hundred fifty-six thousand, eight hundred twenty".