64743715521 has 12 divisors (see below), whose sum is σ = 93520936548. Its totient is φ = 43161444864.

The previous prime is 64743715511. The next prime is 64743715573. The reversal of 64743715521 is 12551734746.

64743715521 is a `hidden beast` number, since 6 + 47 + 437 + 155 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 9089715600 + 55653999921 = 95340^2 + 235911^2 .

It is not a de Polignac number, because 64743715521 - 2⁵ = 64743715489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64743715511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 595261 + ... + 695573.

It is an arithmetic number, because the mean of its divisors is an integer number (7793411379).

Almost surely, 2^64743715521 is an apocalyptic number.

It is an amenable number.

64743715521 is a deficient number, since it is larger than the sum of its proper divisors (28777221027).

64743715521 is a wasteful number, since it uses less digits than its factorization.

64743715521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172032 (or 172029 counting only the distinct ones).

The product of its digits is 705600, while the sum is 45.

The spelling of 64743715521 in words is "sixty-four billion, seven hundred forty-three million, seven hundred fifteen thousand, five hundred twenty-one".