21766522 has 4 divisors (see below), whose sum is σ = 32649786. Its totient is φ = 10883260.

The previous prime is 21766513. The next prime is 21766543. The reversal of 21766522 is 22566712.

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., 18913801 + 2852721 = 4349^2 + 1689^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 as a sum of consecutive naturals, namely, 5441629 + ... + 5441632.

Almost surely, 2^21766522 is an apocalyptic number.

21766522 is a deficient number, since it is larger than the sum of its proper divisors (10883264).

21766522 is a wasteful number, since it uses less digits than its factorization.

21766522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10883263.

The product of its digits is 10080, while the sum is 31.

The square root of 21766522 is about 4665.4605346096. The cubic root of 21766522 is about 279.2091715583.

The spelling of 21766522 in words is "twenty-one million, seven hundred sixty-six thousand, five hundred twenty-two".