861252587520 has 832 divisors, whose sum is σ = 3083934303744. Its totient is φ = 203843174400.

The previous prime is 861252587491. The next prime is 861252587579. The reversal of 861252587520 is 25785252168.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (832).

It is a super-3 number, since 3×861252587520³ (a number of 37 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4462448544 + ... + 4462448736.

Almost surely, 2^861252587520 is an apocalyptic number.

861252587520 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861252587520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1541967151872).

861252587520 is an abundant number, since it is smaller than the sum of its proper divisors (2222681716224).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

861252587520 is a wasteful number, since it uses less digits than its factorization.

861252587520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426 (or 404 counting only the distinct ones).

The product of its (nonzero) digits is 2688000, while the sum is 51.

The spelling of 861252587520 in words is "eight hundred sixty-one billion, two hundred fifty-two million, five hundred eighty-seven thousand, five hundred twenty".