21226616 has 8 divisors (see below), whose sum is σ = 39799920. Its totient is φ = 10613304.

The previous prime is 21226613. The next prime is 21226627. The reversal of 21226616 is 61662212.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×21226616² = 901138453622912, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21226613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1326656 + ... + 1326671.

It is an arithmetic number, because the mean of its divisors is an integer number (4974990).

Almost surely, 2^21226616 is an apocalyptic number.

It is an amenable number.

21226616 is a deficient number, since it is larger than the sum of its proper divisors (18573304).

21226616 is a wasteful number, since it uses less digits than its factorization.

21226616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2653333 (or 2653329 counting only the distinct ones).

The product of its digits is 1728, while the sum is 26.

The square root of 21226616 is about 4607.2351795844. The cubic root of 21226616 is about 276.8812760426.

Adding to 21226616 its reverse (61662212), we get a palindrome (82888828).

The spelling of 21226616 in words is "twenty-one million, two hundred twenty-six thousand, six hundred sixteen".