647874361985 has 4 divisors (see below), whose sum is σ = 777449234388. Its totient is φ = 518299489584.

The previous prime is 647874361973. The next prime is 647874362087. The reversal of 647874361985 is 589163478746.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 589163478746 = 2 ⋅294581739373.

It can be written as a sum of positive squares in 2 ways, for example, as 97025397121 + 550848964864 = 311489^2 + 742192^2 .

It is a cyclic number.

It is not a de Polignac number, because 647874361985 - 2¹⁰ = 647874360961 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64787436194 + ... + 64787436203.

It is an arithmetic number, because the mean of its divisors is an integer number (194362308597).

Almost surely, 2^647874361985 is an apocalyptic number.

It is an amenable number.

647874361985 is a deficient number, since it is larger than the sum of its proper divisors (129574872403).

647874361985 is a wasteful number, since it uses less digits than its factorization.

647874361985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129574872402.

The product of its digits is 243855360, while the sum is 68.

The spelling of 647874361985 in words is "six hundred forty-seven billion, eight hundred seventy-four million, three hundred sixty-one thousand, nine hundred eighty-five".