21226408 has 48 divisors (see below), whose sum is σ = 46713780. Its totient is φ = 9015552.

The previous prime is 21226393. The next prime is 21226409. The reversal of 21226408 is 80462212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20958084 + 268324 = 4578^2 + 518^2 .

It is not an unprimeable number, because it can be changed into a prime (21226409) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 67660 + ... + 67972.

Almost surely, 2^21226408 is an apocalyptic number.

21226408 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21226408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23356890).

21226408 is an abundant number, since it is smaller than the sum of its proper divisors (25487372).

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

21226408 is a wasteful number, since it uses less digits than its factorization.

21226408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506 (or 495 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 21226408 is about 4607.2126063380. The cubic root of 21226408 is about 276.8803716514.

The spelling of 21226408 in words is "twenty-one million, two hundred twenty-six thousand, four hundred eight".