21820448 has 24 divisors (see below), whose sum is σ = 46264428. Its totient is φ = 10070784.

The previous prime is 21820439. The next prime is 21820457. The reversal of 21820448 is 84402812.

It is an interprime number because it is at equal distance from previous prime (21820439) and next prime (21820457).

It can be written as a sum of positive squares in 2 ways, for example, as 20539024 + 1281424 = 4532^2 + 1132^2 .

It is a super-2 number, since 2×21820448² = 952263901841408, 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 21820448.

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, 25811 + ... + 26642.

Almost surely, 2^21820448 is an apocalyptic number.

It is an amenable number.

21820448 is an abundant number, since it is smaller than the sum of its proper divisors (24443980).

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

21820448 is a wasteful number, since it uses less digits than its factorization.

21820448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52476 (or 52468 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 29.

The square root of 21820448 is about 4671.2362389415. The cubic root of 21820448 is about 279.4395592569.

The spelling of 21820448 in words is "twenty-one million, eight hundred twenty thousand, four hundred forty-eight".