648642365761 has 4 divisors (see below), whose sum is σ = 698537932372. Its totient is φ = 598746799152.

The previous prime is 648642365729. The next prime is 648642365779. The reversal of 648642365761 is 167563246846.

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 307287292225 + 341355073536 = 554335^2 + 584256^2 .

It is a cyclic number.

It is not a de Polignac number, because 648642365761 - 2⁵ = 648642365729 is a prime.

It is a super-3 number, since 3×648642365761³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 648642365696 and 648642365705.

It is not an unprimeable number, because it can be changed into a prime (648642305761) 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, 24947783286 + ... + 24947783311.

It is an arithmetic number, because the mean of its divisors is an integer number (174634483093).

Almost surely, 2^648642365761 is an apocalyptic number.

It is an amenable number.

648642365761 is a deficient number, since it is larger than the sum of its proper divisors (49895566611).

648642365761 is a wasteful number, since it uses less digits than its factorization.

648642365761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49895566610.

The product of its digits is 34836480, while the sum is 58.

The spelling of 648642365761 in words is "six hundred forty-eight billion, six hundred forty-two million, three hundred sixty-five thousand, seven hundred sixty-one".