662721 has 4 divisors (see below), whose sum is σ = 883632. Its totient is φ = 441812.

The previous prime is 662719. The next prime is 662743. The reversal of 662721 is 127266.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 662721 - 2¹ = 662719 is a prime.

It is a D-number.

662721 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 662691 and 662700.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 662721.

It is not an unprimeable number, because it can be changed into a prime (662771) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 110451 + ... + 110456.

It is an arithmetic number, because the mean of its divisors is an integer number (220908).

2⁶⁶²⁷²¹ is an apocalyptic number.

It is an amenable number.

662721 is a deficient number, since it is larger than the sum of its proper divisors (220911).

662721 is a wasteful number, since it uses less digits than its factorization.

662721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220910.

The product of its digits is 1008, while the sum is 24.

The square root of 662721 is about 814.0767777059. The cubic root of 662721 is about 87.1853624815.

Adding to 662721 its reverse (127266), we get a palindrome (789987).

The spelling of 662721 in words is "six hundred sixty-two thousand, seven hundred twenty-one".