64465635875821 has 4 divisors (see below), whose sum is σ = 64465761332700. Its totient is φ = 64465510418944.

The previous prime is 64465635875819. The next prime is 64465635875843. The reversal of 64465635875821 is 12857853656446.

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 33436959300900 + 31028676574921 = 5782470^2 + 5570339^2 .

It is a cyclic number.

It is not a de Polignac number, because 64465635875821 - 2¹ = 64465635875819 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 (64465635875621) 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, 61954486 + ... + 62986423.

It is an arithmetic number, because the mean of its divisors is an integer number (16116440333175).

Almost surely, 2^{64465635875821} is an apocalyptic number.

It is an amenable number.

64465635875821 is a deficient number, since it is larger than the sum of its proper divisors (125456879).

64465635875821 is a wasteful number, since it uses less digits than its factorization.

64465635875821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125456878.

The product of its digits is 1161216000, while the sum is 70.

The spelling of 64465635875821 in words is "sixty-four trillion, four hundred sixty-five billion, six hundred thirty-five million, eight hundred seventy-five thousand, eight hundred twenty-one".