217972438068 has 72 divisors (see below), whose sum is σ = 638905468096. Its totient is φ = 56616215040.

The previous prime is 217972438037. The next prime is 217972438097. The reversal of 217972438068 is 860834279712.

It is a junction number, because it is equal to n+sod(n) for n = 217972437999 and 217972438017.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10712605 + ... + 10732932.

Almost surely, 2^217972438068 is an apocalyptic number.

217972438068 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

217972438068 is an abundant number, since it is smaller than the sum of its proper divisors (420933030028).

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

217972438068 is a wasteful number, since it uses less digits than its factorization.

217972438068 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21445573 (or 21445560 counting only the distinct ones).

The product of its (nonzero) digits is 8128512, while the sum is 57.

The spelling of 217972438068 in words is "two hundred seventeen billion, nine hundred seventy-two million, four hundred thirty-eight thousand, sixty-eight".