21214620 has 144 divisors (see below), whose sum is σ = 74692800. Its totient is φ = 4773888.

The previous prime is 21214619. The next prime is 21214643. The reversal of 21214620 is 2641212.

21214620 is a `hidden beast` number, since 21 + 21 + 4 + 620 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 21214593 and 21214602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 142306 + ... + 142454.

It is an arithmetic number, because the mean of its divisors is an integer number (518700).

Almost surely, 2^21214620 is an apocalyptic number.

21214620 is a gapful number since it is divisible by the number (20) 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 21214620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37346400).

21214620 is an abundant number, since it is smaller than the sum of its proper divisors (53478180).

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

21214620 is a wasteful number, since it uses less digits than its factorization.

21214620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 284 (or 279 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21214620 is about 4605.9331302137. The cubic root of 21214620 is about 276.8291073615.

Adding to 21214620 its reverse (2641212), we get a palindrome (23855832).

The spelling of 21214620 in words is "twenty-one million, two hundred fourteen thousand, six hundred twenty".