21830440 has 32 divisors (see below), whose sum is σ = 49277160. Its totient is φ = 8704000.

The previous prime is 21830387. The next prime is 21830453. The reversal of 21830440 is 4403812.

It can be written as a sum of positive squares in 4 ways, for example, as 19909444 + 1920996 = 4462^2 + 1386^2 .

It is a super-2 number, since 2×21830440² = 953136221187200, which contains 22 as substring.

It is an unprimeable number.

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, 15360 + ... + 16720.

Almost surely, 2^21830440 is an apocalyptic number.

21830440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21830440 is an abundant number, since it is smaller than the sum of its proper divisors (27446720).

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

21830440 is a wasteful number, since it uses less digits than its factorization.

21830440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1773 (or 1769 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 21830440 is about 4672.3056406875. The cubic root of 21830440 is about 279.4822063188.

The spelling of 21830440 in words is "twenty-one million, eight hundred thirty thousand, four hundred forty".