21821460 has 24 divisors (see below), whose sum is σ = 61100256. Its totient is φ = 5819040.

The previous prime is 21821441. The next prime is 21821461. The reversal of 21821460 is 6412812.

It is a super-2 number, since 2×21821460² = 952352233063200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21821460.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21821461) 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 7 ways as a sum of consecutive naturals, for example, 181786 + ... + 181905.

It is an arithmetic number, because the mean of its divisors is an integer number (2545844).

Almost surely, 2^21821460 is an apocalyptic number.

21821460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21821460 is an abundant number, since it is smaller than the sum of its proper divisors (39278796).

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

21821460 is a wasteful number, since it uses less digits than its factorization.

21821460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363703 (or 363701 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21821460 is about 4671.3445601882. The cubic root of 21821460 is about 279.4438791875.

The spelling of 21821460 in words is "twenty-one million, eight hundred twenty-one thousand, four hundred sixty".