861694525440 has 1224 divisors, whose sum is σ = 3566378995920. Its totient is φ = 191839076352.

The previous prime is 861694525423. The next prime is 861694525451. The reversal of 861694525440 is 44525496168.

It is a happy number.

861694525440 is a `hidden beast` number, since 8 + 6 + 1 + 6 + 94 + 5 + 2 + 544 + 0 = 666.

It is a super-3 number, since 3×861694525440³ (a number of 37 digits) contains 333 as substring.

It is a congruent number.

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 71 ways as a sum of consecutive naturals, for example, 9681960916 + ... + 9681961004.

It is an arithmetic number, because the mean of its divisors is an integer number (2913708330).

Almost surely, 2^861694525440 is an apocalyptic number.

861694525440 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 861694525440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1783189497960).

861694525440 is an abundant number, since it is smaller than the sum of its proper divisors (2704684470480).

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

861694525440 is an equidigital number, since it uses as much as digits as its factorization.

861694525440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 8294400, while the sum is 54.

The spelling of 861694525440 in words is "eight hundred sixty-one billion, six hundred ninety-four million, five hundred twenty-five thousand, four hundred forty".