816553 has 8 divisors (see below), whose sum is σ = 868680. Its totient is φ = 766080.

The previous prime is 816547. The next prime is 816559. The reversal of 816553 is 355618.

It is an interprime number because it is at equal distance from previous prime (816547) and next prime (816559).

It can be written as a sum of positive squares in 4 ways, for example, as 56169 + 760384 = 237^2 + 872^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 816553 - 2⁵ = 816521 is a prime.

It is a super-3 number, since 3×816553³ = 1633331699680633131, which contains 333 as substring.

It is a Duffinian number.

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (816559) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 693 + ... + 1453.

It is an arithmetic number, because the mean of its divisors is an integer number (108585).

2⁸¹⁶⁵⁵³ is an apocalyptic number.

It is an amenable number.

816553 is a deficient number, since it is larger than the sum of its proper divisors (52127).

816553 is a wasteful number, since it uses less digits than its factorization.

816553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 827.

The product of its digits is 3600, while the sum is 28.

The square root of 816553 is about 903.6332220542. The cubic root of 816553 is about 93.4676792593.

It can be divided in two parts, 816 and 553, that added together give a square (1369 = 37²).

The spelling of 816553 in words is "eight hundred sixteen thousand, five hundred fifty-three".