861996038400 has 648 divisors, whose sum is σ = 3652585844544. Its totient is φ = 197025177600.

The previous prime is 861996038363. The next prime is 861996038413. The reversal of 861996038400 is 4830699168.

861996038400 is a `hidden beast` number, since 8 + 61 + 99 + 60 + 38 + 400 = 666.

It is a tau number, because it is divible by the number of its divisors (648).

It is a super-3 number, since 3×861996038400³ (a number of 37 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 10846810 + ... + 10925990.

Almost surely, 2^861996038400 is an apocalyptic number.

861996038400 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 861996038400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1826292922272).

861996038400 is an abundant number, since it is smaller than the sum of its proper divisors (2790589806144).

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

861996038400 is an equidigital number, since it uses as much as digits as its factorization.

861996038400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79229 (or 79198 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 54.

The spelling of 861996038400 in words is "eight hundred sixty-one billion, nine hundred ninety-six million, thirty-eight thousand, four hundred".