21135268 has 36 divisors (see below), whose sum is σ = 46941552. Its totient is φ = 8233680.

The previous prime is 21135259. The next prime is 21135293. The reversal of 21135268 is 86253112.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 2746 + ... + 7057.

It is an arithmetic number, because the mean of its divisors is an integer number (1303932).

Almost surely, 2^21135268 is an apocalyptic number.

21135268 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21135268 is an abundant number, since it is smaller than the sum of its proper divisors (25806284).

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

21135268 is a wasteful number, since it uses less digits than its factorization.

21135268 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9832 (or 9823 counting only the distinct ones).

The product of its digits is 2880, while the sum is 28.

The square root of 21135268 is about 4597.3109531551. The cubic root of 21135268 is about 276.4835219577.

It can be divided in two parts, 2113 and 5268, that added together give a triangular number (7381 = T₁₂₁).

The spelling of 21135268 in words is "twenty-one million, one hundred thirty-five thousand, two hundred sixty-eight".