861635546880 has 288 divisors, whose sum is σ = 2803144216320. Its totient is φ = 225499545600.

The previous prime is 861635546867. The next prime is 861635546899. The reversal of 861635546880 is 88645536168.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 152472055 + ... + 152477705.

It is an arithmetic number, because the mean of its divisors is an integer number (9733139640).

Almost surely, 2^861635546880 is an apocalyptic number.

861635546880 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 861635546880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1401572108160).

861635546880 is an abundant number, since it is smaller than the sum of its proper divisors (1941508669440).

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

861635546880 is a wasteful number, since it uses less digits than its factorization.

861635546880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6407 (or 6393 counting only the distinct ones).

The product of its (nonzero) digits is 33177600, while the sum is 60.

The spelling of 861635546880 in words is "eight hundred sixty-one billion, six hundred thirty-five million, five hundred forty-six thousand, eight hundred eighty".