1213517218 has 4 divisors (see below), whose sum is σ = 1820275830. Its totient is φ = 606758608.

The previous prime is 1213517197. The next prime is 1213517219. The reversal of 1213517218 is 8127153121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 786970809 + 426546409 = 28053^2 + 20653^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1213517218.

It is not an unprimeable number, because it can be changed into a prime (1213517219) 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, 303379303 + ... + 303379306.

Almost surely, 2^1213517218 is an apocalyptic number.

1213517218 is a deficient number, since it is larger than the sum of its proper divisors (606758612).

1213517218 is an equidigital number, since it uses as much as digits as its factorization.

1213517218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606758611.

The product of its digits is 3360, while the sum is 31.

The square root of 1213517218 is about 34835.5740300056. The cubic root of 1213517218 is about 1066.6337325552.

The spelling of 1213517218 in words is "one billion, two hundred thirteen million, five hundred seventeen thousand, two hundred eighteen".