21335120 has 20 divisors (see below), whose sum is σ = 49604340. Its totient is φ = 8534016.

The previous prime is 21335117. The next prime is 21335123. The reversal of 21335120 is 2153312.

It is an interprime number because it is at equal distance from previous prime (21335117) and next prime (21335123).

It can be written as a sum of positive squares in 2 ways, for example, as 13017664 + 8317456 = 3608^2 + 2884^2 .

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 (21335123) 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, 133265 + ... + 133424.

It is an arithmetic number, because the mean of its divisors is an integer number (2480217).

Almost surely, 2^21335120 is an apocalyptic number.

21335120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21335120 is an abundant number, since it is smaller than the sum of its proper divisors (28269220).

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

21335120 is a wasteful number, since it uses less digits than its factorization.

21335120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266702 (or 266696 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21335120 is about 4618.9955618078. The cubic root of 21335120 is about 277.3522520583.

Adding to 21335120 its reverse (2153312), we get a palindrome (23488432).

The spelling of 21335120 in words is "twenty-one million, three hundred thirty-five thousand, one hundred twenty".