21415104 has 140 divisors (see below), whose sum is σ = 67491864. Its totient is φ = 6718464.

The previous prime is 21415099. The next prime is 21415129. The reversal of 21415104 is 40151412.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1259704 + ... + 1259720.

Almost surely, 2^21415104 is an apocalyptic number.

21415104 is a gapful number since it is divisible by the number (24) 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 21415104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33745932).

21415104 is an abundant number, since it is smaller than the sum of its proper divisors (46076760).

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

21415104 is an frugal number, since it uses more digits than its factorization.

21415104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56 (or 22 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 21415104 is about 4627.6456216958. The cubic root of 21415104 is about 277.6984117911.

Adding to 21415104 its reverse (40151412), we get a palindrome (61566516).

The spelling of 21415104 in words is "twenty-one million, four hundred fifteen thousand, one hundred four".