64006561 has 4 divisors (see below), whose sum is σ = 64082452. Its totient is φ = 63930672.

The previous prime is 64006549. The next prime is 64006589. The reversal of 64006561 is 16560046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3400336 + 60606225 = 1844^2 + 7785^2 .

It is a cyclic number.

It is not a de Polignac number, because 64006561 - 2¹⁷ = 63875489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64006531) 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, 36666 + ... + 38371.

It is an arithmetic number, because the mean of its divisors is an integer number (16020613).

Almost surely, 2^64006561 is an apocalyptic number.

It is an amenable number.

64006561 is a deficient number, since it is larger than the sum of its proper divisors (75891).

64006561 is an equidigital number, since it uses as much as digits as its factorization.

64006561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75890.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 64006561 is about 8000.4100519911. The cubic root of 64006561 is about 400.0136682829.

It can be divided in two parts, 6400 and 6561, that multiplied together give a square (41990400 = 6480²).

The spelling of 64006561 in words is "sixty-four million, six thousand, five hundred sixty-one".