821601 has 24 divisors (see below), whose sum is σ = 1331616. Its totient is φ = 483840.

The previous prime is 821573. The next prime is 821603. The reversal of 821601 is 106128.

It is not a de Polignac number, because 821601 - 2⁹ = 821089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821603) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4161 + ... + 4353.

It is an arithmetic number, because the mean of its divisors is an integer number (55484).

2⁸²¹⁶⁰¹ is an apocalyptic number.

It is an amenable number.

821601 is a deficient number, since it is larger than the sum of its proper divisors (510015).

821601 is a wasteful number, since it uses less digits than its factorization.

821601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253 (or 250 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 821601 is about 906.4220871095. The cubic root of 821601 is about 93.6598920871.

Adding to 821601 its reverse (106128), we get a palindrome (927729).

It can be divided in two parts, 8 and 21601, that added together give a square (21609 = 147²).

The spelling of 821601 in words is "eight hundred twenty-one thousand, six hundred one".