9215965521 has 72 divisors (see below), whose sum is σ = 15727369320. Its totient is φ = 5184635904.

The previous prime is 9215965511. The next prime is 9215965537. The reversal of 9215965521 is 1255695129.

9215965521 is a `hidden beast` number, since 9 + 2 + 1 + 5 + 96 + 552 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 755645121 + 8460320400 = 27489^2 + 91980^2 .

It is not a de Polignac number, because 9215965521 - 2⁷ = 9215965393 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (9215965511) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 8620575 + ... + 8621643.

It is an arithmetic number, because the mean of its divisors is an integer number (218435685).

Almost surely, 2^9215965521 is an apocalyptic number.

It is an amenable number.

9215965521 is a deficient number, since it is larger than the sum of its proper divisors (6511403799).

9215965521 is a wasteful number, since it uses less digits than its factorization.

9215965521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1375 (or 1365 counting only the distinct ones).

The product of its digits is 243000, while the sum is 45.

The square root of 9215965521 is about 95999.8204217070. The cubic root of 9215965521 is about 2096.5905007648.

The spelling of 9215965521 in words is "nine billion, two hundred fifteen million, nine hundred sixty-five thousand, five hundred twenty-one".