634531521 has 32 divisors (see below), whose sum is σ = 972905472. Its totient is φ = 364795200.

The previous prime is 634531517. The next prime is 634531523. The reversal of 634531521 is 125135436.

It is not a de Polignac number, because 634531521 - 2² = 634531517 is a prime.

It is a super-4 number, since 4×634531521⁴ (a number of 36 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (634531523) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30346 + ... + 46796.

It is an arithmetic number, because the mean of its divisors is an integer number (30403296).

Almost surely, 2^634531521 is an apocalyptic number.

It is an amenable number.

634531521 is a deficient number, since it is larger than the sum of its proper divisors (338373951).

634531521 is a wasteful number, since it uses less digits than its factorization.

634531521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16533.

The product of its digits is 10800, while the sum is 30.

The square root of 634531521 is about 25189.9091105943. The cubic root of 634531521 is about 859.3123767057.

Adding to 634531521 its reverse (125135436), we get a palindrome (759666957).

The spelling of 634531521 in words is "six hundred thirty-four million, five hundred thirty-one thousand, five hundred twenty-one".