634921 has 4 divisors (see below), whose sum is σ = 725632. Its totient is φ = 544212.

The previous prime is 634903. The next prime is 634927. The reversal of 634921 is 129436.

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 634921 - 2⁷ = 634793 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

634921 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (634927) 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, 45345 + ... + 45358.

It is an arithmetic number, because the mean of its divisors is an integer number (181408).

2⁶³⁴⁹²¹ is an apocalyptic number.

It is an amenable number.

634921 is a deficient number, since it is larger than the sum of its proper divisors (90711).

634921 is an equidigital number, since it uses as much as digits as its factorization.

634921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90710.

The product of its digits is 1296, while the sum is 25.

The square root of 634921 is about 796.8193019750. The cubic root of 634921 is about 85.9488157661.

The spelling of 634921 in words is "six hundred thirty-four thousand, nine hundred twenty-one".