21094020 has 120 divisors (see below), whose sum is σ = 68607000. Its totient is φ = 5419008.

The previous prime is 21094019. The next prime is 21094057. The reversal of 21094020 is 2049012.

It can be written as a sum of positive squares in 4 ways, for example, as 3048516 + 18045504 = 1746^2 + 4248^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21093984 and 21094002.

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 39 ways as a sum of consecutive naturals, for example, 46756 + ... + 47204.

It is an arithmetic number, because the mean of its divisors is an integer number (571725).

Almost surely, 2^21094020 is an apocalyptic number.

21094020 is a gapful number since it is divisible by the number (20) 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 21094020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34303500).

21094020 is an abundant number, since it is smaller than the sum of its proper divisors (47512980).

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

21094020 is a wasteful number, since it uses less digits than its factorization.

21094020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499 (or 488 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 21094020 is about 4592.8226615013. The cubic root of 21094020 is about 276.3035412831.

The spelling of 21094020 in words is "twenty-one million, ninety-four thousand, twenty".