618821 has 12 divisors (see below), whose sum is σ = 733932. Its totient is φ = 520128.

The previous prime is 618799. The next prime is 618823. The reversal of 618821 is 128816.

It can be written as a sum of positive squares in 2 ways, for example, as 470596 + 148225 = 686^2 + 385^2 .

It is a de Polignac number, because none of the positive numbers 2^k-618821 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (618823) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3491 + ... + 3663.

It is an arithmetic number, because the mean of its divisors is an integer number (61161).

2⁶¹⁸⁸²¹ is an apocalyptic number.

It is an amenable number.

618821 is a deficient number, since it is larger than the sum of its proper divisors (115111).

618821 is a wasteful number, since it uses less digits than its factorization.

618821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260 (or 253 counting only the distinct ones).

The product of its digits is 768, while the sum is 26.

The square root of 618821 is about 786.6517653956. The cubic root of 618821 is about 85.2161052379.

The spelling of 618821 in words is "six hundred eighteen thousand, eight hundred twenty-one".