21621116 has 24 divisors (see below), whose sum is σ = 41416704. Its totient is φ = 9794480.

The previous prime is 21621113. The next prime is 21621121. The reversal of 21621116 is 61112612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621113) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16211 + ... + 17493.

It is an arithmetic number, because the mean of its divisors is an integer number (1725696).

Almost surely, 2^21621116 is an apocalyptic number.

It is an amenable number.

21621116 is a deficient number, since it is larger than the sum of its proper divisors (19795588).

21621116 is a wasteful number, since it uses less digits than its factorization.

21621116 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1681 (or 1679 counting only the distinct ones).

The product of its digits is 144, while the sum is 20.

The square root of 21621116 is about 4649.8511804143. The cubic root of 21621116 is about 278.5860521173.

Adding to 21621116 its reverse (61112612), we get a palindrome (82733728).

The spelling of 21621116 in words is "twenty-one million, six hundred twenty-one thousand, one hundred sixteen".