21435040 has 96 divisors (see below), whose sum is σ = 58242240. Its totient is φ = 7372800.

The previous prime is 21435023. The next prime is 21435049. The reversal of 21435040 is 4053412.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a junction number, because it is equal to n+sod(n) for n = 21434999 and 21435017.

It is not an unprimeable number, because it can be changed into a prime (21435049) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33120 + ... + 33760.

It is an arithmetic number, because the mean of its divisors is an integer number (606690).

Almost surely, 2^21435040 is an apocalyptic number.

21435040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21435040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29121120).

21435040 is an abundant number, since it is smaller than the sum of its proper divisors (36807200).

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

21435040 is a wasteful number, since it uses less digits than its factorization.

21435040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 686 (or 678 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21435040 is about 4629.7991317119. The cubic root of 21435040 is about 277.7845578197.

Adding to 21435040 its reverse (4053412), we get a palindrome (25488452).

The spelling of 21435040 in words is "twenty-one million, four hundred thirty-five thousand, forty".