21027616 has 12 divisors (see below), whose sum is σ = 41398182. Its totient is φ = 10513792.

The previous prime is 21027613. The next prime is 21027637. The reversal of 21027616 is 61672012.

It can be written as a sum of positive squares in only one way, i.e., 14288400 + 6739216 = 3780^2 + 2596^2 .

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21027613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 328525 + ... + 328588.

Almost surely, 2^21027616 is an apocalyptic number.

It is an amenable number.

21027616 is a deficient number, since it is larger than the sum of its proper divisors (20370566).

21027616 is an equidigital number, since it uses as much as digits as its factorization.

21027616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 657123 (or 657115 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21027616 is about 4585.5878576252. The cubic root of 21027616 is about 276.0133018864.

Adding to 21027616 its reverse (61672012), we get a palindrome (82699628).

The spelling of 21027616 in words is "twenty-one million, twenty-seven thousand, six hundred sixteen".