678029521 has 9 divisors (see below), whose sum is σ = 734564379. Its totient is φ = 625560936.

The previous prime is 678029491. The next prime is 678029537. The reversal of 678029521 is 125920876.

The square root of 678029521 is 26039.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 100300225 + 577729296 = 10015^2 + 24036^2 .

It is not a de Polignac number, because 678029521 - 2⁷ = 678029393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (678029591) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 337506 + ... + 339508.

Almost surely, 2^678029521 is an apocalyptic number.

678029521 is the 26039-th square number.

678029521 is the 13020-th centered octagonal number.

It is an amenable number.

678029521 is a deficient number, since it is larger than the sum of its proper divisors (56534858).

678029521 is an frugal number, since it uses more digits than its factorization.

678029521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4032 (or 2016 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 40.

The cubic root of 678029521 is about 878.5157145650.

The spelling of 678029521 in words is "six hundred seventy-eight million, twenty-nine thousand, five hundred twenty-one".