217742949 has 6 divisors (see below), whose sum is σ = 314517606. Its totient is φ = 145161960.

The previous prime is 217742929. The next prime is 217742951. The reversal of 217742949 is 949247712.

It is a happy number.

217742949 is a `hidden beast` number, since 217 + 7 + 429 + 4 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 187964100 + 29778849 = 13710^2 + 5457^2 .

It is not a de Polignac number, because 217742949 - 2¹² = 217738853 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217742929) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12096822 + ... + 12096839.

It is an arithmetic number, because the mean of its divisors is an integer number (52419601).

Almost surely, 2^217742949 is an apocalyptic number.

It is an amenable number.

217742949 is a deficient number, since it is larger than the sum of its proper divisors (96774657).

217742949 is a wasteful number, since it uses less digits than its factorization.

217742949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24193667 (or 24193664 counting only the distinct ones).

The product of its digits is 254016, while the sum is 45.

The square root of 217742949 is about 14756.1156474189. The cubic root of 217742949 is about 601.6095202138.

The spelling of 217742949 in words is "two hundred seventeen million, seven hundred forty-two thousand, nine hundred forty-nine".