861252587521 has 16 divisors (see below), whose sum is σ = 929373554304. Its totient is φ = 795218621184.

The previous prime is 861252587491. The next prime is 861252587579. The reversal of 861252587521 is 125785252168.

It is a happy number.

It is not a de Polignac number, because 861252587521 - 2²¹ = 861250490369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861252582521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2111070 + ... + 2485783.

It is an arithmetic number, because the mean of its divisors is an integer number (58085847144).

Almost surely, 2^861252587521 is an apocalyptic number.

It is an amenable number.

861252587521 is a deficient number, since it is larger than the sum of its proper divisors (68120966783).

861252587521 is a wasteful number, since it uses less digits than its factorization.

861252587521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4597080.

The product of its digits is 2688000, while the sum is 52.

The spelling of 861252587521 in words is "eight hundred sixty-one billion, two hundred fifty-two million, five hundred eighty-seven thousand, five hundred twenty-one".