21116620 has 24 divisors (see below), whose sum is σ = 50680224. Its totient is φ = 7239936.

The previous prime is 21116597. The next prime is 21116629. The reversal of 21116620 is 2661112.

It is not an unprimeable number, because it can be changed into a prime (21116629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75277 + ... + 75556.

It is an arithmetic number, because the mean of its divisors is an integer number (2111676).

Almost surely, 2^21116620 is an apocalyptic number.

21116620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21116620 is an abundant number, since it is smaller than the sum of its proper divisors (29563604).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21116620 is a wasteful number, since it uses less digits than its factorization.

21116620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150849 (or 150847 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 21116620 is about 4595.2823634680. The cubic root of 21116620 is about 276.4021826874.

Adding to 21116620 its reverse (2661112), we get a palindrome (23777732).

It can be divided in two parts, 21116 and 620, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21116620 in words is "twenty-one million, one hundred sixteen thousand, six hundred twenty".