729551521 has 12 divisors (see below), whose sum is σ = 768016444. Its totient is φ = 692798400.

The previous prime is 729551509. The next prime is 729551527. The reversal of 729551521 is 125155927.

It can be written as a sum of positive squares in 6 ways, for example, as 24117921 + 705433600 = 4911^2 + 26560^2 .

It is not a de Polignac number, because 729551521 - 2⁷ = 729551393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (729551527) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 44191 + ... + 58411.

Almost surely, 2^729551521 is an apocalyptic number.

It is an amenable number.

729551521 is a deficient number, since it is larger than the sum of its proper divisors (38464923).

729551521 is a wasteful number, since it uses less digits than its factorization.

729551521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14340 (or 14311 counting only the distinct ones).

The product of its digits is 31500, while the sum is 37.

The square root of 729551521 is about 27010.2114208682. The cubic root of 729551521 is about 900.2269061626.

The spelling of 729551521 in words is "seven hundred twenty-nine million, five hundred fifty-one thousand, five hundred twenty-one".