21409266 has 8 divisors (see below), whose sum is σ = 42818544. Its totient is φ = 7136420.

The previous prime is 21409249. The next prime is 21409277. The reversal of 21409266 is 66290412.

It is a sphenic number, since it is the product of 3 distinct primes.

21409266 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1784100 + ... + 1784111.

It is an arithmetic number, because the mean of its divisors is an integer number (5352318).

Almost surely, 2^21409266 is an apocalyptic number.

21409266 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21409266 is a wasteful number, since it uses less digits than its factorization.

21409266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3568216.

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 21409266 is about 4627.0148043852. The cubic root of 21409266 is about 277.6731749198.

Adding to 21409266 its reverse (66290412), we get a palindrome (87699678).

The spelling of 21409266 in words is "twenty-one million, four hundred nine thousand, two hundred sixty-six".