21214521 has 16 divisors (see below), whose sum is σ = 33278400. Its totient is φ = 13310784.

The previous prime is 21214517. The next prime is 21214541. The reversal of 21214521 is 12541212.

21214521 is a `hidden beast` number, since 212 + 1 + 452 + 1 = 666.

It is not a de Polignac number, because 21214521 - 2² = 21214517 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21214494 and 21214503.

It is not an unprimeable number, because it can be changed into a prime (21214541) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 22651 + ... + 23568.

It is an arithmetic number, because the mean of its divisors is an integer number (2079900).

Almost surely, 2^21214521 is an apocalyptic number.

It is an amenable number.

21214521 is a deficient number, since it is larger than the sum of its proper divisors (12063879).

21214521 is a wasteful number, since it uses less digits than its factorization.

21214521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46245 (or 46239 counting only the distinct ones).

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

The square root of 21214521 is about 4605.9223831932. The cubic root of 21214521 is about 276.8286767446.

Adding to 21214521 its reverse (12541212), we get a palindrome (33755733).

The spelling of 21214521 in words is "twenty-one million, two hundred fourteen thousand, five hundred twenty-one".