672821 has 4 divisors (see below), whose sum is σ = 688512. Its totient is φ = 657132.

The previous prime is 672817. The next prime is 672823. The reversal of 672821 is 128276.

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 672821 - 2² = 672817 is a prime.

It is a Duffinian 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 672821.

It is not an unprimeable number, because it can be changed into a prime (672823) 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, 7781 + ... + 7866.

It is an arithmetic number, because the mean of its divisors is an integer number (172128).

2⁶⁷²⁸²¹ is an apocalyptic number.

It is an amenable number.

672821 is a deficient number, since it is larger than the sum of its proper divisors (15691).

672821 is a wasteful number, since it uses less digits than its factorization.

672821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15690.

The product of its digits is 1344, while the sum is 26.

The square root of 672821 is about 820.2566671475. The cubic root of 672821 is about 87.6260387693.

It can be divided in two parts, 6 and 72821, that added together give a palindrome (72827).

The spelling of 672821 in words is "six hundred seventy-two thousand, eight hundred twenty-one".