21823720 has 32 divisors (see below), whose sum is σ = 49572000. Its totient is φ = 8646208.

The previous prime is 21823717. The next prime is 21823741. The reversal of 21823720 is 2732812.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1731 + ... + 6829.

It is an arithmetic number, because the mean of its divisors is an integer number (1549125).

Almost surely, 2^21823720 is an apocalyptic number.

21823720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21823720 is an abundant number, since it is smaller than the sum of its proper divisors (27748280).

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

21823720 is a wasteful number, since it uses less digits than its factorization.

21823720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5217 (or 5213 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 21823720 is about 4671.5864543001. The cubic root of 21823720 is about 279.4535259811.

The spelling of 21823720 in words is "twenty-one million, eight hundred twenty-three thousand, seven hundred twenty".