64521247 has 4 divisors (see below), whose sum is σ = 73738576. Its totient is φ = 55303920.

The previous prime is 64521241. The next prime is 64521257. The reversal of 64521247 is 74212546.

64521247 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74212546 = 2 ⋅37106273.

It is a de Polignac number, because none of the positive numbers 2^k-64521247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64521241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4608654 + ... + 4608667.

It is an arithmetic number, because the mean of its divisors is an integer number (18434644).

Almost surely, 2^64521247 is an apocalyptic number.

64521247 is a deficient number, since it is larger than the sum of its proper divisors (9217329).

64521247 is an equidigital number, since it uses as much as digits as its factorization.

64521247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9217328.

The product of its digits is 13440, while the sum is 31.

The square root of 64521247 is about 8032.5118736296. The cubic root of 64521247 is about 401.0829964007.

The spelling of 64521247 in words is "sixty-four million, five hundred twenty-one thousand, two hundred forty-seven".