21246320 has 20 divisors (see below), whose sum is σ = 49397880. Its totient is φ = 8498496.

The previous prime is 21246317. The next prime is 21246341. The reversal of 21246320 is 2364212.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×21246320² = 902812227084800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21246292 and 21246301.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132710 + ... + 132869.

It is an arithmetic number, because the mean of its divisors is an integer number (2469894).

Almost surely, 2^21246320 is an apocalyptic number.

21246320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21246320 is an abundant number, since it is smaller than the sum of its proper divisors (28151560).

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

21246320 is a wasteful number, since it uses less digits than its factorization.

21246320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265592 (or 265586 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 21246320 is about 4609.3730593216. The cubic root of 21246320 is about 276.9669229402.

The spelling of 21246320 in words is "twenty-one million, two hundred forty-six thousand, three hundred twenty".