718821 has 16 divisors (see below), whose sum is σ = 1081600. Its totient is φ = 471744.

The previous prime is 718813. The next prime is 718841. The reversal of 718821 is 128817.

It is not a de Polignac number, because 718821 - 2³ = 718813 is a prime.

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

It is a Duffinian number.

718821 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 718821.

It is not an unprimeable number, because it can be changed into a prime (718801) 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, 1965 + ... + 2301.

It is an arithmetic number, because the mean of its divisors is an integer number (67600).

2⁷¹⁸⁸²¹ is an apocalyptic number.

It is an amenable number.

718821 is a deficient number, since it is larger than the sum of its proper divisors (362779).

718821 is a wasteful number, since it uses less digits than its factorization.

718821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425 (or 419 counting only the distinct ones).

The product of its digits is 896, while the sum is 27.

The square root of 718821 is about 847.8331203722. The cubic root of 718821 is about 89.5791462017.

The spelling of 718821 in words is "seven hundred eighteen thousand, eight hundred twenty-one".