639552581691543 has 24 divisors (see below), whose sum is σ = 995293440045632. Its totient is φ = 393399179206848.

The previous prime is 639552581691493. The next prime is 639552581691587. The reversal of 639552581691543 is 345196185255936.

639552581691543 is a `hidden beast` number, since 6 + 3 + 9 + 5 + 525 + 8 + 1 + 6 + 91 + 5 + 4 + 3 = 666.

It is not a de Polignac number, because 639552581691543 - 2⁶ = 639552581691479 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639552581691343) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1191677071 + ... + 1192213632.

Almost surely, 2^{639552581691543} is an apocalyptic number.

639552581691543 is a deficient number, since it is larger than the sum of its proper divisors (355740858354089).

639552581691543 is a wasteful number, since it uses less digits than its factorization.

639552581691543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2383893015 (or 2383893012 counting only the distinct ones).

The product of its digits is 1049760000, while the sum is 72.

The spelling of 639552581691543 in words is "six hundred thirty-nine trillion, five hundred fifty-two billion, five hundred eighty-one million, six hundred ninety-one thousand, five hundred forty-three".