821536 has 12 divisors (see below), whose sum is σ = 1617462. Its totient is φ = 410752.

The previous prime is 821519. The next prime is 821551. The reversal of 821536 is 635128.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 571536 + 250000 = 756^2 + 500^2 .

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 821536.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12805 + ... + 12868.

2⁸²¹⁵³⁶ is an apocalyptic number.

It is an amenable number.

821536 is a deficient number, since it is larger than the sum of its proper divisors (795926).

821536 is a wasteful number, since it uses less digits than its factorization.

821536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25683 (or 25675 counting only the distinct ones).

The product of its digits is 1440, while the sum is 25.

The square root of 821536 is about 906.3862311399. The cubic root of 821536 is about 93.6574220911.

The spelling of 821536 in words is "eight hundred twenty-one thousand, five hundred thirty-six".