64623531565 has 4 divisors (see below), whose sum is σ = 77548237884. Its totient is φ = 51698825248.

The previous prime is 64623531563. The next prime is 64623531569. The reversal of 64623531565 is 56513532646.

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 13075007716 + 51548523849 = 114346^2 + 227043^2 .

It is a cyclic number.

It is not a de Polignac number, because 64623531565 - 2¹ = 64623531563 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 (64623531563) 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, 6462353152 + ... + 6462353161.

It is an arithmetic number, because the mean of its divisors is an integer number (19387059471).

Almost surely, 2^64623531565 is an apocalyptic number.

It is an amenable number.

64623531565 is a deficient number, since it is larger than the sum of its proper divisors (12924706319).

64623531565 is a wasteful number, since it uses less digits than its factorization.

64623531565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12924706318.

The product of its digits is 1944000, while the sum is 46.

The spelling of 64623531565 in words is "sixty-four billion, six hundred twenty-three million, five hundred thirty-one thousand, five hundred sixty-five".