216578209536 has 864 divisors, whose sum is σ = 737968637952. Its totient is φ = 62884823040.

The previous prime is 216578209531. The next prime is 216578209537. The reversal of 216578209536 is 635902875612.

216578209536 is a `hidden beast` number, since 2 + 16 + 5 + 78 + 20 + 9 + 536 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a super-2 number, since 2×216578209536² (a number of 23 digits) contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216578209531) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1328700591 + ... + 1328700753.

It is an arithmetic number, because the mean of its divisors is an integer number (854130368).

Almost surely, 2^216578209536 is an apocalyptic number.

216578209536 is a gapful number since it is divisible by the number (26) 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 216578209536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (368984318976).

216578209536 is an abundant number, since it is smaller than the sum of its proper divisors (521390428416).

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

216578209536 is a wasteful number, since it uses less digits than its factorization.

216578209536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 5443200, while the sum is 54.

The spelling of 216578209536 in words is "two hundred sixteen billion, five hundred seventy-eight million, two hundred nine thousand, five hundred thirty-six".