21296808 has 96 divisors (see below), whose sum is σ = 63303240. Its totient is φ = 6428160.

The previous prime is 21296797. The next prime is 21296809. The reversal of 21296808 is 80869212.

It can be written as a sum of positive squares in 4 ways, for example, as 8892324 + 12404484 = 2982^2 + 3522^2 .

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is not an unprimeable number, because it can be changed into a prime (21296809) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 56910 + ... + 57282.

Almost surely, 2^21296808 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 21296808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31651620).

21296808 is an abundant number, since it is smaller than the sum of its proper divisors (42006432).

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

21296808 is a wasteful number, since it uses less digits than its factorization.

21296808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 459 (or 452 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 21296808 is about 4614.8464763197. The cubic root of 21296808 is about 277.1861364980.

It can be divided in two parts, 212 and 96808, that added together give a triangular number (97020 = T₄₄₀).

The spelling of 21296808 in words is "twenty-one million, two hundred ninety-six thousand, eight hundred eight".