217998149 has 2 divisors, whose sum is σ = 217998150. Its totient is φ = 217998148.

The previous prime is 217998139. The next prime is 217998203. The reversal of 217998149 is 941899712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 137124100 + 80874049 = 11710^2 + 8993^2 .

It is a cyclic number.

It is not a de Polignac number, because 217998149 - 2²⁴ = 201220933 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 217998097 and 217998106.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217998119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108999074 + 108999075.

It is an arithmetic number, because the mean of its divisors is an integer number (108999075).

Almost surely, 2^217998149 is an apocalyptic number.

It is an amenable number.

217998149 is a deficient number, since it is larger than the sum of its proper divisors (1).

217998149 is an equidigital number, since it uses as much as digits as its factorization.

217998149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 326592, while the sum is 50.

The square root of 217998149 is about 14764.7603773309. The cubic root of 217998149 is about 601.8444620855.

The spelling of 217998149 in words is "two hundred seventeen million, nine hundred ninety-eight thousand, one hundred forty-nine".