21310263 has 32 divisors (see below), whose sum is σ = 34372800. Its totient is φ = 12970368.

The previous prime is 21310253. The next prime is 21310271. The reversal of 21310263 is 36201312.

It is not a de Polignac number, because 21310263 - 2⁶ = 21310199 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37981 + ... + 38537.

It is an arithmetic number, because the mean of its divisors is an integer number (1074150).

Almost surely, 2^21310263 is an apocalyptic number.

21310263 is a deficient number, since it is larger than the sum of its proper divisors (13062537).

21310263 is a wasteful number, since it uses less digits than its factorization.

21310263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688 (or 682 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21310263 is about 4616.3040411134. The cubic root of 21310263 is about 277.2444982068.

Adding to 21310263 its reverse (36201312), we get a palindrome (57511575).

The spelling of 21310263 in words is "twenty-one million, three hundred ten thousand, two hundred sixty-three".