21807708 has 48 divisors (see below), whose sum is σ = 56090496. Its totient is φ = 6552000.

The previous prime is 21807707. The next prime is 21807727. The reversal of 21807708 is 80770812.

It is a super-2 number, since 2×21807708² = 951152256426528, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21807707) 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 15 ways as a sum of consecutive naturals, for example, 5083 + ... + 8333.

It is an arithmetic number, because the mean of its divisors is an integer number (1168552).

Almost surely, 2^21807708 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21807708, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28045248).

21807708 is an abundant number, since it is smaller than the sum of its proper divisors (34282788).

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

21807708 is a wasteful number, since it uses less digits than its factorization.

21807708 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3314 (or 3312 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 33.

The square root of 21807708 is about 4669.8723751298. The cubic root of 21807708 is about 279.3851645126.

The spelling of 21807708 in words is "twenty-one million, eight hundred seven thousand, seven hundred eight".