21680116 has 6 divisors (see below), whose sum is σ = 37940210. Its totient is φ = 10840056.

The previous prime is 21680101. The next prime is 21680143. The reversal of 21680116 is 61108612.

It can be written as a sum of positive squares in only one way, i.e., 15968016 + 5712100 = 3996^2 + 2390^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2710011 + ... + 2710018.

Almost surely, 2^21680116 is an apocalyptic number.

It is an amenable number.

21680116 is a deficient number, since it is larger than the sum of its proper divisors (16260094).

21680116 is a wasteful number, since it uses less digits than its factorization.

21680116 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5420033 (or 5420031 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 21680116 is about 4656.1911472791. The cubic root of 21680116 is about 278.8392251252.

Adding to 21680116 its reverse (61108612), we get a palindrome (82788728).

The spelling of 21680116 in words is "twenty-one million, six hundred eighty thousand, one hundred sixteen".