21820548 has 12 divisors (see below), whose sum is σ = 50914640. Its totient is φ = 7273512.

The previous prime is 21820543. The next prime is 21820553. The reversal of 21820548 is 84502812.

It is an interprime number because it is at equal distance from previous prime (21820543) and next prime (21820553).

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21820548² = 952272630040608, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21820541) 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 3 ways as a sum of consecutive naturals, for example, 909178 + ... + 909201.

Almost surely, 2^21820548 is an apocalyptic number.

It is an amenable number.

21820548 is an abundant number, since it is smaller than the sum of its proper divisors (29094092).

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

21820548 is a wasteful number, since it uses less digits than its factorization.

21820548 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1818386 (or 1818384 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 21820548 is about 4671.2469427338. The cubic root of 21820548 is about 279.4399861334.

The spelling of 21820548 in words is "twenty-one million, eight hundred twenty thousand, five hundred forty-eight".