21434320 has 20 divisors (see below), whose sum is σ = 49834980. Its totient is φ = 8573696.

The previous prime is 21434293. The next prime is 21434323. The reversal of 21434320 is 2343412.

It can be written as a sum of positive squares in 2 ways, for example, as 15303744 + 6130576 = 3912^2 + 2476^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21434323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 133885 + ... + 134044.

It is an arithmetic number, because the mean of its divisors is an integer number (2491749).

Almost surely, 2^21434320 is an apocalyptic number.

21434320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21434320 is an abundant number, since it is smaller than the sum of its proper divisors (28400660).

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

21434320 is a wasteful number, since it uses less digits than its factorization.

21434320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267942 (or 267936 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 21434320 is about 4629.7213739058. The cubic root of 21434320 is about 277.7814475367.

Adding to 21434320 its reverse (2343412), we get a palindrome (23777732).

The spelling of 21434320 in words is "twenty-one million, four hundred thirty-four thousand, three hundred twenty".