21764266 has 4 divisors (see below), whose sum is σ = 32646402. Its totient is φ = 10882132.

The previous prime is 21764261. The next prime is 21764273. The reversal of 21764266 is 66246712.

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

It can be written as a sum of positive squares in only one way, i.e., 11363641 + 10400625 = 3371^2 + 3225^2 .

It is not an unprimeable number, because it can be changed into a prime (21764261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5441065 + ... + 5441068.

Almost surely, 2^21764266 is an apocalyptic number.

21764266 is a deficient number, since it is larger than the sum of its proper divisors (10882136).

21764266 is a wasteful number, since it uses less digits than its factorization.

21764266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10882135.

The product of its digits is 24192, while the sum is 34.

The square root of 21764266 is about 4665.2187515700. The cubic root of 21764266 is about 279.1995249757.

The spelling of 21764266 in words is "twenty-one million, seven hundred sixty-four thousand, two hundred sixty-six".