21417508 has 36 divisors (see below), whose sum is σ = 45505152. Its totient is φ = 8778000.

The previous prime is 21417499. The next prime is 21417509. The reversal of 21417508 is 80571412.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (21417509) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 2133 + ... + 6883.

It is an arithmetic number, because the mean of its divisors is an integer number (1264032).

Almost surely, 2^21417508 is an apocalyptic number.

21417508 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 21417508, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22752576).

21417508 is an abundant number, since it is smaller than the sum of its proper divisors (24087644).

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

21417508 is a wasteful number, since it uses less digits than its factorization.

21417508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4792 (or 4783 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 21417508 is about 4627.9053577185. The cubic root of 21417508 is about 277.7088026193.

The spelling of 21417508 in words is "twenty-one million, four hundred seventeen thousand, five hundred eight".