64601821 has 4 divisors (see below), whose sum is σ = 66829500. Its totient is φ = 62374144.

The previous prime is 64601809. The next prime is 64601851. The reversal of 64601821 is 12810646.

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 49196196 + 15405625 = 7014^2 + 3925^2 .

It is a cyclic number.

It is not a de Polignac number, because 64601821 - 2¹⁵ = 64569053 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64601821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64601851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1113796 + ... + 1113853.

It is an arithmetic number, because the mean of its divisors is an integer number (16707375).

Almost surely, 2^64601821 is an apocalyptic number.

It is an amenable number.

64601821 is a deficient number, since it is larger than the sum of its proper divisors (2227679).

64601821 is a wasteful number, since it uses less digits than its factorization.

64601821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2227678.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 64601821 is about 8037.5258008917. The cubic root of 64601821 is about 401.2498841561.

It can be divided in two parts, 6460 and 1821, that added together give a square (8281 = 91²).

The spelling of 64601821 in words is "sixty-four million, six hundred one thousand, eight hundred twenty-one".