21415212 has 96 divisors (see below), whose sum is σ = 68364800. Its totient is φ = 5645376.

The previous prime is 21415211. The next prime is 21415213. The reversal of 21415212 is 21251412.

21415212 is a `hidden beast` number, since 2 + 141 + 521 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (21415211) and next prime (21415213).

It is a super-2 number, since 2×21415212² = 917222610009888, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (21415211) 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 31 ways as a sum of consecutive naturals, for example, 8739 + ... + 10917.

Almost surely, 2^21415212 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 21415212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34182400).

21415212 is an abundant number, since it is smaller than the sum of its proper divisors (46949588).

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

21415212 is a wasteful number, since it uses less digits than its factorization.

21415212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2212 (or 2204 counting only the distinct ones).

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

The square root of 21415212 is about 4627.6572906818. The cubic root of 21415212 is about 277.6988786170.

Adding to 21415212 its reverse (21251412), we get a palindrome (42666624).

The spelling of 21415212 in words is "twenty-one million, four hundred fifteen thousand, two hundred twelve".