21417408 has 126 divisors (see below), whose sum is σ = 65419224. Its totient is φ = 6697728.

The previous prime is 21417377. The next prime is 21417437. The reversal of 21417408 is 80471412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 207885 + ... + 207987.

Almost surely, 2^21417408 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 21417408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32709612).

21417408 is an abundant number, since it is smaller than the sum of its proper divisors (44001816).

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

21417408 is a wasteful number, since it uses less digits than its factorization.

21417408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159 (or 127 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 21417408 is about 4627.8945536821. The cubic root of 21417408 is about 277.7083704040.

The spelling of 21417408 in words is "twenty-one million, four hundred seventeen thousand, four hundred eight".