21307266 has 16 divisors (see below), whose sum is σ = 47349600. Its totient is φ = 7102404.

The previous prime is 21307243. The next prime is 21307271. The reversal of 21307266 is 66270312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

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, 197236 + ... + 197343.

It is an arithmetic number, because the mean of its divisors is an integer number (2959350).

Almost surely, 2^21307266 is an apocalyptic number.

21307266 is an abundant number, since it is smaller than the sum of its proper divisors (26042334).

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

21307266 is a wasteful number, since it uses less digits than its factorization.

21307266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394590 (or 394584 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 27.

The square root of 21307266 is about 4615.9794193649. The cubic root of 21307266 is about 277.2315007023.

Adding to 21307266 its reverse (66270312), we get a palindrome (87577578).

The spelling of 21307266 in words is "twenty-one million, three hundred seven thousand, two hundred sixty-six".