21231708 has 48 divisors (see below), whose sum is σ = 52819200. Its totient is φ = 6614784.

The previous prime is 21231703. The next prime is 21231713. The reversal of 21231708 is 80713212.

It is an interprime number because it is at equal distance from previous prime (21231703) and next prime (21231713).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40335 + ... + 40857.

It is an arithmetic number, because the mean of its divisors is an integer number (1100400).

Almost surely, 2^21231708 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 21231708, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26409600).

21231708 is an abundant number, since it is smaller than the sum of its proper divisors (31587492).

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

21231708 is a wasteful number, since it uses less digits than its factorization.

21231708 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 746 (or 744 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 21231708 is about 4607.7877555287. The cubic root of 21231708 is about 276.9034143921.

The spelling of 21231708 in words is "twenty-one million, two hundred thirty-one thousand, seven hundred eight".