217920901 has 8 divisors (see below), whose sum is σ = 237996864. Its totient is φ = 197889120.

The previous prime is 217920893. The next prime is 217920919. The reversal of 217920901 is 109029712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 217920901 - 2³ = 217920893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217920301) 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, 265 + ... + 20878.

It is an arithmetic number, because the mean of its divisors is an integer number (29749608).

Almost surely, 2^217920901 is an apocalyptic number.

It is an amenable number.

217920901 is a deficient number, since it is larger than the sum of its proper divisors (20075963).

217920901 is a wasteful number, since it uses less digits than its factorization.

217920901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22091.

The product of its (nonzero) digits is 2268, while the sum is 31.

The square root of 217920901 is about 14762.1441870753. The cubic root of 217920901 is about 601.7733654979.

The spelling of 217920901 in words is "two hundred seventeen million, nine hundred twenty thousand, nine hundred one".