21310320 has 40 divisors (see below), whose sum is σ = 66062736. Its totient is φ = 5682688.

The previous prime is 21310319. The next prime is 21310321. The reversal of 21310320 is 2301312.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21310319) and next prime (21310321).

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 (12).

It is a junction number, because it is equal to n+sod(n) for n = 21310296 and 21310305.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44157 + ... + 44636.

Almost surely, 2^21310320 is an apocalyptic number.

21310320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21310320 is an abundant number, since it is smaller than the sum of its proper divisors (44752416).

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

21310320 is a wasteful number, since it uses less digits than its factorization.

21310320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88809 (or 88803 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21310320 is about 4616.3102148794. The cubic root of 21310320 is about 277.2447453948.

Adding to 21310320 its reverse (2301312), we get a palindrome (23611632).

The spelling of 21310320 in words is "twenty-one million, three hundred ten thousand, three hundred twenty".