21211416 has 64 divisors (see below), whose sum is σ = 59299200. Its totient is φ = 7025184.

The previous prime is 21211403. The next prime is 21211433. The reversal of 21211416 is 61411212.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60955 + ... + 61301.

It is an arithmetic number, because the mean of its divisors is an integer number (926550).

Almost surely, 2^21211416 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 21211416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29649600).

21211416 is an abundant number, since it is smaller than the sum of its proper divisors (38087784).

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

21211416 is a wasteful number, since it uses less digits than its factorization.

21211416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645 (or 635 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 21211416 is about 4605.5853048228. The cubic root of 21211416 is about 276.8151703515.

Adding to 21211416 its reverse (61411212), we get a palindrome (82622628).

It can be divided in two parts, 212 and 11416, that added together give a triangular number (11628 = T₁₅₂).

The spelling of 21211416 in words is "twenty-one million, two hundred eleven thousand, four hundred sixteen".