21635072 has 56 divisors (see below), whose sum is σ = 45872400. Its totient is φ = 10174464.

The previous prime is 21635069. The next prime is 21635137. The reversal of 21635072 is 27053612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155579 + ... + 155717.

It is an arithmetic number, because the mean of its divisors is an integer number (819150).

Almost surely, 2^21635072 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 21635072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22936200).

21635072 is an abundant number, since it is smaller than the sum of its proper divisors (24237328).

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

21635072 is an equidigital number, since it uses as much as digits as its factorization.

21635072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 184 (or 160 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 21635072 is about 4651.3516315153. The cubic root of 21635072 is about 278.6459798089.

Adding to 21635072 its reverse (27053612), we get a palindrome (48688684).

The spelling of 21635072 in words is "twenty-one million, six hundred thirty-five thousand, seventy-two".