21034320 has 40 divisors (see below), whose sum is σ = 65207136. Its totient is φ = 5609088.

The previous prime is 21034313. The next prime is 21034331. The reversal of 21034320 is 2343012.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a zygodrome in base 4.

It is a self number, because there is not a number n which added to its sum of digits gives 21034320.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43582 + ... + 44061.

Almost surely, 2^21034320 is an apocalyptic number.

21034320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21034320 is an abundant number, since it is smaller than the sum of its proper divisors (44172816).

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

21034320 is a wasteful number, since it uses less digits than its factorization.

21034320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87659 (or 87653 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21034320 is about 4586.3187852569. The cubic root of 21034320 is about 276.0426315160.

Adding to 21034320 its reverse (2343012), we get a palindrome (23377332).

The spelling of 21034320 in words is "twenty-one million, thirty-four thousand, three hundred twenty".