64015521 has 4 divisors (see below), whose sum is σ = 85354032. Its totient is φ = 42677012.

The previous prime is 64015507. The next prime is 64015529. The reversal of 64015521 is 12551046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 64015521 - 2²³ = 55626913 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 64015491 and 64015500.

It is not an unprimeable number, because it can be changed into a prime (64015529) 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, 10669251 + ... + 10669256.

It is an arithmetic number, because the mean of its divisors is an integer number (21338508).

Almost surely, 2^64015521 is an apocalyptic number.

It is an amenable number.

64015521 is a deficient number, since it is larger than the sum of its proper divisors (21338511).

64015521 is a wasteful number, since it uses less digits than its factorization.

64015521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21338510.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 64015521 is about 8000.9700036933. The cubic root of 64015521 is about 400.0323328031.

Adding to 64015521 its reverse (12551046), we get a palindrome (76566567).

It can be divided in two parts, 640 and 15521, that added together give a palindrome (16161).

The spelling of 64015521 in words is "sixty-four million, fifteen thousand, five hundred twenty-one".