21261852 has 60 divisors (see below), whose sum is σ = 56105280. Its totient is φ = 7020864.

The previous prime is 21261839. The next prime is 21261869. The reversal of 21261852 is 25816212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 44149 + ... + 44627.

It is an arithmetic number, because the mean of its divisors is an integer number (935088).

Almost surely, 2^21261852 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21261852, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28052640).

21261852 is an abundant number, since it is smaller than the sum of its proper divisors (34843428).

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

21261852 is a wasteful number, since it uses less digits than its factorization.

21261852 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632 (or 621 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 21261852 is about 4611.0575793412. The cubic root of 21261852 is about 277.0343981923.

The spelling of 21261852 in words is "twenty-one million, two hundred sixty-one thousand, eight hundred fifty-two".