64621646209 has 4 divisors (see below), whose sum is σ = 64628284500. Its totient is φ = 64615007920.

The previous prime is 64621646207. The next prime is 64621646249. The reversal of 64621646209 is 90264612646.

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 36692551809 + 27929094400 = 191553^2 + 167120^2 .

It is a cyclic number.

It is not a de Polignac number, because 64621646209 - 2¹ = 64621646207 is a prime.

It is a super-2 number, since 2×64621646209² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64621646207) 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, 3304522 + ... + 3324019.

It is an arithmetic number, because the mean of its divisors is an integer number (16157071125).

Almost surely, 2^64621646209 is an apocalyptic number.

It is an amenable number.

64621646209 is a deficient number, since it is larger than the sum of its proper divisors (6638291).

64621646209 is an equidigital number, since it uses as much as digits as its factorization.

64621646209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6638290.

The product of its (nonzero) digits is 746496, while the sum is 46.

The spelling of 64621646209 in words is "sixty-four billion, six hundred twenty-one million, six hundred forty-six thousand, two hundred nine".