218787949 has 2 divisors, whose sum is σ = 218787950. Its totient is φ = 218787948.

The previous prime is 218787923. The next prime is 218787967. The reversal of 218787949 is 949787812.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 217562500 + 1225449 = 14750^2 + 1107^2 .

It is a cyclic number.

It is not a de Polignac number, because 218787949 - 2¹¹ = 218785901 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 218787949.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218787979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109393974 + 109393975.

It is an arithmetic number, because the mean of its divisors is an integer number (109393975).

Almost surely, 2^218787949 is an apocalyptic number.

It is an amenable number.

218787949 is a deficient number, since it is larger than the sum of its proper divisors (1).

218787949 is an equidigital number, since it uses as much as digits as its factorization.

218787949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2032128, while the sum is 55.

The square root of 218787949 is about 14791.4823124662. The cubic root of 218787949 is about 602.5704068820.

The spelling of 218787949 in words is "two hundred eighteen million, seven hundred eighty-seven thousand, nine hundred forty-nine".