21286966 has 4 divisors (see below), whose sum is σ = 31930452. Its totient is φ = 10643482.

The previous prime is 21286963. The next prime is 21286981. The reversal of 21286966 is 66968212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21286961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5321740 + ... + 5321743.

It is an arithmetic number, because the mean of its divisors is an integer number (7982613).

Almost surely, 2^21286966 is an apocalyptic number.

21286966 is a deficient number, since it is larger than the sum of its proper divisors (10643486).

21286966 is a wasteful number, since it uses less digits than its factorization.

21286966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10643485.

The product of its digits is 62208, while the sum is 40.

The square root of 21286966 is about 4613.7800120942. The cubic root of 21286966 is about 277.1434307819.

It can be divided in two parts, 212 and 86966, that added together give a palindrome (87178).

The spelling of 21286966 in words is "twenty-one million, two hundred eighty-six thousand, nine hundred sixty-six".