21299456 has 72 divisors (see below), whose sum is σ = 46603200. Its totient is φ = 9676800.

The previous prime is 21299423. The next prime is 21299461. The reversal of 21299456 is 65499212.

It is a Harshad number since it is a multiple of its sum of digits (38).

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 7 ways as a sum of consecutive naturals, for example, 140981 + ... + 141131.

Almost surely, 2^21299456 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 21299456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23301600).

21299456 is an abundant number, since it is smaller than the sum of its proper divisors (25303744).

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

21299456 is a wasteful number, since it uses less digits than its factorization.

21299456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215 (or 201 counting only the distinct ones).

The product of its digits is 38880, while the sum is 38.

The square root of 21299456 is about 4615.1333675204. The cubic root of 21299456 is about 277.1976242676.

The spelling of 21299456 in words is "twenty-one million, two hundred ninety-nine thousand, four hundred fifty-six".