21907296 has 144 divisors (see below), whose sum is σ = 67026960. Its totient is φ = 6773760.

The previous prime is 21907289. The next prime is 21907307. The reversal of 21907296 is 69270912.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21907296.

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 23 ways as a sum of consecutive naturals, for example, 359106 + ... + 359166.

It is an arithmetic number, because the mean of its divisors is an integer number (465465).

Almost surely, 2^21907296 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 21907296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33513480).

21907296 is an abundant number, since it is smaller than the sum of its proper divisors (45119664).

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

21907296 is a wasteful number, since it uses less digits than its factorization.

21907296 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149 (or 138 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 21907296 is about 4680.5230476946. The cubic root of 21907296 is about 279.8098028057.

The spelling of 21907296 in words is "twenty-one million, nine hundred seven thousand, two hundred ninety-six".