506765515721 has 4 divisors (see below), whose sum is σ = 506904855492. Its totient is φ = 506626175952.

The previous prime is 506765515657. The next prime is 506765515741. The reversal of 506765515721 is 127515567605.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127515567605 = 5 ⋅25503113521.

It can be written as a sum of positive squares in 2 ways, for example, as 37787083321 + 468978432400 = 194389^2 + 684820^2 .

It is a cyclic number.

It is not a de Polignac number, because 506765515721 - 2⁶ = 506765515657 is a prime.

It is a super-2 number, since 2×506765515721² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 506765515721.

It is not an unprimeable number, because it can be changed into a prime (506765515741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69664430 + ... + 69671703.

It is an arithmetic number, because the mean of its divisors is an integer number (126726213873).

Almost surely, 2^506765515721 is an apocalyptic number.

It is an amenable number.

506765515721 is a deficient number, since it is larger than the sum of its proper divisors (139339771).

506765515721 is a wasteful number, since it uses less digits than its factorization.

506765515721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139339770.

The product of its (nonzero) digits is 2205000, while the sum is 50.

The spelling of 506765515721 in words is "five hundred six billion, seven hundred sixty-five million, five hundred fifteen thousand, seven hundred twenty-one".