634871521 has 4 divisors (see below), whose sum is σ = 637038612. Its totient is φ = 632704432.

The previous prime is 634871513. The next prime is 634871543. The reversal of 634871521 is 125178436.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 614296225 + 20575296 = 24785^2 + 4536^2 .

It is a cyclic number.

It is not a de Polignac number, because 634871521 - 2³ = 634871513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (634871581) 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, 1083106 + ... + 1083691.

It is an arithmetic number, because the mean of its divisors is an integer number (159259653).

Almost surely, 2^634871521 is an apocalyptic number.

It is an amenable number.

634871521 is a deficient number, since it is larger than the sum of its proper divisors (2167091).

634871521 is a wasteful number, since it uses less digits than its factorization.

634871521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2167090.

The product of its digits is 40320, while the sum is 37.

The square root of 634871521 is about 25196.6569409515. The cubic root of 634871521 is about 859.4658306216.

The spelling of 634871521 in words is "six hundred thirty-four million, eight hundred seventy-one thousand, five hundred twenty-one".