64821605 has 4 divisors (see below), whose sum is σ = 77785932. Its totient is φ = 51857280.

The previous prime is 64821599. The next prime is 64821607. The reversal of 64821605 is 50612846.

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 12952801 + 51868804 = 3599^2 + 7202^2 .

It is not a de Polignac number, because 64821605 - 2⁶ = 64821541 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 (64821607) 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, 6482156 + ... + 6482165.

It is an arithmetic number, because the mean of its divisors is an integer number (19446483).

Almost surely, 2^64821605 is an apocalyptic number.

It is an amenable number.

64821605 is a deficient number, since it is larger than the sum of its proper divisors (12964327).

64821605 is a wasteful number, since it uses less digits than its factorization.

64821605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12964326.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 64821605 is about 8051.1865585142. The cubic root of 64821605 is about 401.7044042833.

The spelling of 64821605 in words is "sixty-four million, eight hundred twenty-one thousand, six hundred five".