8242642521 has 27 divisors (see below), whose sum is σ = 12156209247. Its totient is φ = 5381971920.

The previous prime is 8242642493. The next prime is 8242642579. The reversal of 8242642521 is 1252462428.

The square root of 8242642521 is 90789.

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

8242642521 is a `hidden beast` number, since 8 + 2 + 4 + 2 + 642 + 5 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 5942097225 + 2300545296 = 77085^2 + 47964^2 .

It is not a de Polignac number, because 8242642521 - 2⁷ = 8242642393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8242642591) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 14435166 + ... + 14435736.

Almost surely, 2^8242642521 is an apocalyptic number.

8242642521 is the 90789-th square number.

8242642521 is the 45395-th centered octagonal number.

It is an amenable number.

8242642521 is a deficient number, since it is larger than the sum of its proper divisors (3913566726).

8242642521 is an frugal number, since it uses more digits than its factorization.

8242642521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1254 (or 627 counting only the distinct ones).

The product of its digits is 61440, while the sum is 36.

The cubic root of 8242642521 is about 2020.0191581524.

Multiplying 8242642521 by its sum of digits (36), we get a square (296735130756 = 544734²).

The spelling of 8242642521 in words is "eight billion, two hundred forty-two million, six hundred forty-two thousand, five hundred twenty-one".