21000364 has 48 divisors (see below), whose sum is σ = 46964736. Its totient is φ = 7977600.

The previous prime is 21000337. The next prime is 21000367. The reversal of 21000364 is 46300012.

It is not an unprimeable number, because it can be changed into a prime (21000367) 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, 11797 + ... + 13459.

It is an arithmetic number, because the mean of its divisors is an integer number (978432).

Almost surely, 2^21000364 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 21000364, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23482368).

21000364 is an abundant number, since it is smaller than the sum of its proper divisors (25964372).

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

21000364 is a wasteful number, since it uses less digits than its factorization.

21000364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1726 (or 1724 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21000364 is about 4582.6154104398. The cubic root of 21000364 is about 275.8940116740.

Adding to 21000364 its reverse (46300012), we get a palindrome (67300376).

The spelling of 21000364 in words is "twenty-one million, three hundred sixty-four", and thus it is an aban number.