7665521 has 4 divisors (see below), whose sum is σ = 8116452. Its totient is φ = 7214592.

The previous prime is 7665517. The next prime is 7665527. The reversal of 7665521 is 1255667.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1255667 = 7 ⋅179381.

It can be written as a sum of positive squares in 2 ways, for example, as 2283121 + 5382400 = 1511^2 + 2320^2 .

It is a cyclic number.

It is not a de Polignac number, because 7665521 - 2² = 7665517 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (7665527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 225440 + ... + 225473.

It is an arithmetic number, because the mean of its divisors is an integer number (2029113).

Almost surely, 2^7665521 is an apocalyptic number.

It is an amenable number.

7665521 is a deficient number, since it is larger than the sum of its proper divisors (450931).

7665521 is a wasteful number, since it uses less digits than its factorization.

7665521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450930.

The product of its digits is 12600, while the sum is 32.

The square root of 7665521 is about 2768.6677301547. The cubic root of 7665521 is about 197.1729008483.

The spelling of 7665521 in words is "seven million, six hundred sixty-five thousand, five hundred twenty-one".