634821 has 8 divisors (see below), whose sum is σ = 923424. Its totient is φ = 384720.

The previous prime is 634817. The next prime is 634841. The reversal of 634821 is 128436.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 634821 - 2² = 634817 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 634791 and 634800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (634841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9586 + ... + 9651.

It is an arithmetic number, because the mean of its divisors is an integer number (115428).

2⁶³⁴⁸²¹ is an apocalyptic number.

It is an amenable number.

634821 is a deficient number, since it is larger than the sum of its proper divisors (288603).

634821 is a wasteful number, since it uses less digits than its factorization.

634821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19251.

The product of its digits is 1152, while the sum is 24.

The square root of 634821 is about 796.7565500201. The cubic root of 634821 is about 85.9443032190.

It can be divided in two parts, 63 and 4821, that added together give a palindrome (4884).

The spelling of 634821 in words is "six hundred thirty-four thousand, eight hundred twenty-one".