21522530 has 16 divisors (see below), whose sum is σ = 39788280. Its totient is φ = 8376192.

The previous prime is 21522521. The next prime is 21522533. The reversal of 21522530 is 3522512.

It can be written as a sum of positive squares in 4 ways, for example, as 19123129 + 2399401 = 4373^2 + 1549^2 .

It is a Curzon number.

It is a nialpdrome in base 9.

It is a zygodrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (21522533) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28715 + ... + 29454.

Almost surely, 2^21522530 is an apocalyptic number.

21522530 is a deficient number, since it is larger than the sum of its proper divisors (18265750).

21522530 is a wasteful number, since it uses less digits than its factorization.

21522530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58213.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 21522530 is about 4639.2380839961. The cubic root of 21522530 is about 278.1619831307.

The spelling of 21522530 in words is "twenty-one million, five hundred twenty-two thousand, five hundred thirty".