21707308 has 48 divisors (see below), whose sum is σ = 46577664. Its totient is φ = 8648640.

The previous prime is 21707299. The next prime is 21707321. The reversal of 21707308 is 80370712.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23373 + ... + 24283.

It is an arithmetic number, because the mean of its divisors is an integer number (970368).

Almost surely, 2^21707308 is an apocalyptic number.

21707308 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21707308, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23288832).

21707308 is an abundant number, since it is smaller than the sum of its proper divisors (24870356).

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

21707308 is a wasteful number, since it uses less digits than its factorization.

21707308 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982 (or 980 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 28.

The square root of 21707308 is about 4659.1102154811. The cubic root of 21707308 is about 278.9557532296.

The spelling of 21707308 in words is "twenty-one million, seven hundred seven thousand, three hundred eight".