7921521 has 24 divisors (see below), whose sum is σ = 11915904. Its totient is φ = 5067360.

The previous prime is 7921519. The next prime is 7921549. The reversal of 7921521 is 1251297.

7921521 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 7921521 - 2¹ = 7921519 is a prime.

It is a d-powerful number, because it can be written as 7⁸ + 9⁵ + 2⁹ + 1 + 5 + 2²¹ + 1 .

It is not an unprimeable number, because it can be changed into a prime (7921561) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25650 + ... + 25956.

It is an arithmetic number, because the mean of its divisors is an integer number (496496).

Almost surely, 2^7921521 is an apocalyptic number.

It is an amenable number.

7921521 is a deficient number, since it is larger than the sum of its proper divisors (3994383).

7921521 is a wasteful number, since it uses less digits than its factorization.

7921521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421 (or 418 counting only the distinct ones).

The product of its digits is 1260, while the sum is 27.

The square root of 7921521 is about 2814.5196748291. The cubic root of 7921521 is about 199.3438580762.

The spelling of 7921521 in words is "seven million, nine hundred twenty-one thousand, five hundred twenty-one".