21008226 has 16 divisors (see below), whose sum is σ = 44488224. Its totient is φ = 6590784.

The previous prime is 21008219. The next prime is 21008237. The reversal of 21008226 is 62280012.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102880 + ... + 103083.

It is an arithmetic number, because the mean of its divisors is an integer number (2780514).

Almost surely, 2^21008226 is an apocalyptic number.

21008226 is an abundant number, since it is smaller than the sum of its proper divisors (23479998).

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

21008226 is a wasteful number, since it uses less digits than its factorization.

21008226 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205985.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21008226 is about 4583.4731372617. The cubic root of 21008226 is about 275.9284366026.

Adding to 21008226 its reverse (62280012), we get a palindrome (83288238).

The spelling of 21008226 in words is "twenty-one million, eight thousand, two hundred twenty-six".