8821521 has 16 divisors (see below), whose sum is σ = 13838400. Its totient is φ = 5534784.

The previous prime is 8821517. The next prime is 8821523. The reversal of 8821521 is 1251288.

It is not a de Polignac number, because 8821521 - 2² = 8821517 is a prime.

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

8821521 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (8821523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9151 + ... + 10068.

It is an arithmetic number, because the mean of its divisors is an integer number (864900).

Almost surely, 2^8821521 is an apocalyptic number.

It is an amenable number.

8821521 is a deficient number, since it is larger than the sum of its proper divisors (5016879).

8821521 is a wasteful number, since it uses less digits than its factorization.

8821521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19245 (or 19239 counting only the distinct ones).

The product of its digits is 1280, while the sum is 27.

The square root of 8821521 is about 2970.1045436146. The cubic root of 8821521 is about 206.6241868407.

It can be divided in two parts, 88 and 21521, that added together give a square (21609 = 147²).

The spelling of 8821521 in words is "eight million, eight hundred twenty-one thousand, five hundred twenty-one".