21434280 has 256 divisors, whose sum is σ = 82944000. Its totient is φ = 4313088.

The previous prime is 21434279. The next prime is 21434293. The reversal of 21434280 is 8243412.

21434280 = T₁₆₉ + T₁₇₀ + ... + T₅₁₀.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21434280.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 271281 + ... + 271359.

It is an arithmetic number, because the mean of its divisors is an integer number (324000).

Almost surely, 2^21434280 is an apocalyptic number.

21434280 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 21434280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41472000).

21434280 is an abundant number, since it is smaller than the sum of its proper divisors (61509720).

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

21434280 is a wasteful number, since it uses less digits than its factorization.

21434280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136 (or 132 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 21434280 is about 4629.7170539894. The cubic root of 21434280 is about 277.7812747412.

Adding to 21434280 its reverse (8243412), we get a palindrome (29677692).

The spelling of 21434280 in words is "twenty-one million, four hundred thirty-four thousand, two hundred eighty".