21854440 has 16 divisors (see below), whose sum is σ = 49172580. Its totient is φ = 8741760.

The previous prime is 21854431. The next prime is 21854461. The reversal of 21854440 is 4445812.

It can be written as a sum of positive squares in 2 ways, for example, as 21511044 + 343396 = 4638^2 + 586^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21854399 and 21854408.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 273141 + ... + 273220.

Almost surely, 2^21854440 is an apocalyptic number.

21854440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21854440 is an abundant number, since it is smaller than the sum of its proper divisors (27318140).

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

21854440 is a wasteful number, since it uses less digits than its factorization.

21854440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 546372 (or 546368 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 28.

The square root of 21854440 is about 4674.8732603141. The cubic root of 21854440 is about 279.5845880755.

The spelling of 21854440 in words is "twenty-one million, eight hundred fifty-four thousand, four hundred forty".