217120640 has 64 divisors (see below), whose sum is σ = 566259120. Its totient is φ = 78950400.

The previous prime is 217120571. The next prime is 217120643. The reversal of 217120640 is 46021712.

It is a tau number, because it is divible by the number of its divisors (64).

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217120643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8381 + ... + 22460.

Almost surely, 2^217120640 is an apocalyptic number.

217120640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

217120640 is an abundant number, since it is smaller than the sum of its proper divisors (349138480).

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

217120640 is a wasteful number, since it uses less digits than its factorization.

217120640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30871 (or 30859 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 23.

The square root of 217120640 is about 14735.0140821107. The cubic root of 217120640 is about 601.0358403252.

The spelling of 217120640 in words is "two hundred seventeen million, one hundred twenty thousand, six hundred forty".