217978941 has 8 divisors (see below), whose sum is σ = 292161024. Its totient is φ = 144558080.

The previous prime is 217978927. The next prime is 217978979. The reversal of 217978941 is 149879712.

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

It is a cyclic number.

It is not a de Polignac number, because 217978941 - 2⁵ = 217978909 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217978141) 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, 189636 + ... + 190781.

It is an arithmetic number, because the mean of its divisors is an integer number (36520128).

Almost surely, 2^217978941 is an apocalyptic number.

It is an amenable number.

217978941 is a deficient number, since it is larger than the sum of its proper divisors (74182083).

217978941 is a wasteful number, since it uses less digits than its factorization.

217978941 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380611.

The product of its digits is 254016, while the sum is 48.

The square root of 217978941 is about 14764.1098952832. The cubic root of 217978941 is about 601.8267852260.

The spelling of 217978941 in words is "two hundred seventeen million, nine hundred seventy-eight thousand, nine hundred forty-one".