217155978000 has 1440 divisors, whose sum is σ = 906134087040. Its totient is φ = 49884595200.

The previous prime is 217155977999. The next prime is 217155978059. The reversal of 217155978000 is 879551712.

217155978000 is a `hidden beast` number, since 2 + 17 + 1 + 559 + 7 + 80 + 0 + 0 = 666.

It is a super-2 number, since 2×217155978000² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 3241133967 + ... + 3241134033.

Almost surely, 2^217155978000 is an apocalyptic number.

217155978000 is a gapful number since it is divisible by the number (20) 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 217155978000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (453067043520).

217155978000 is an abundant number, since it is smaller than the sum of its proper divisors (688978109040).

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

217155978000 is an equidigital number, since it uses as much as digits as its factorization.

217155978000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146 (or 109 counting only the distinct ones).

The product of its (nonzero) digits is 176400, while the sum is 45.

The spelling of 217155978000 in words is "two hundred seventeen billion, one hundred fifty-five million, nine hundred seventy-eight thousand".