21310280 has 16 divisors (see below), whose sum is σ = 47948220. Its totient is φ = 8524096.

The previous prime is 21310279. The next prime is 21310297. The reversal of 21310280 is 8201312.

It can be written as a sum of positive squares in 2 ways, for example, as 20811844 + 498436 = 4562^2 + 706^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 266339 + ... + 266418.

Almost surely, 2^21310280 is an apocalyptic number.

21310280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21310280 is an abundant number, since it is smaller than the sum of its proper divisors (26637940).

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

21310280 is a wasteful number, since it uses less digits than its factorization.

21310280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 532768 (or 532764 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 21310280 is about 4616.3058824129. The cubic root of 21310280 is about 277.2445719296.

Adding to 21310280 its reverse (8201312), we get a palindrome (29511592).

The spelling of 21310280 in words is "twenty-one million, three hundred ten thousand, two hundred eighty".