634905 has 16 divisors (see below), whose sum is σ = 1128960. Its totient is φ = 338544.

The previous prime is 634903. The next prime is 634927. The reversal of 634905 is 509436.

It is a happy number.

It is not a de Polignac number, because 634905 - 2¹ = 634903 is a prime.

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

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

It is not an unprimeable number, because it can be changed into a prime (634901) 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, 2217 + ... + 2486.

It is an arithmetic number, because the mean of its divisors is an integer number (70560).

2⁶³⁴⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

634905 is a deficient number, since it is larger than the sum of its proper divisors (494055).

634905 is a wasteful number, since it uses less digits than its factorization.

634905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4717 (or 4711 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 634905 is about 796.8092619944. The cubic root of 634905 is about 85.9480937904.

The spelling of 634905 in words is "six hundred thirty-four thousand, nine hundred five".