1218649 has 2 divisors, whose sum is σ = 1218650. Its totient is φ = 1218648.

The previous prime is 1218631. The next prime is 1218653. The reversal of 1218649 is 9468121.

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., 1210000 + 8649 = 1100^2 + 93^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218649 - 2⁵ = 1218617 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1218649.

It is not a weakly prime, because it can be changed into another prime (1218449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609324 + 609325.

It is an arithmetic number, because the mean of its divisors is an integer number (609325).

2^1218649 is an apocalyptic number.

It is an amenable number.

1218649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218649 is an equidigital number, since it uses as much as digits as its factorization.

1218649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 31.

The square root of 1218649 is about 1103.9243633510. The cubic root of 1218649 is about 106.8135162702.

It can be divided in two parts, 121 and 8649, that multiplied together give a square (1046529 = 1023²).

The spelling of 1218649 in words is "one million, two hundred eighteen thousand, six hundred forty-nine".