1218671281 has 2 divisors, whose sum is σ = 1218671282. Its totient is φ = 1218671280.

The previous prime is 1218671239. The next prime is 1218671291. The reversal of 1218671281 is 1821768121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 696960000 + 521711281 = 26400^2 + 22841^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218671281 - 2⁹ = 1218670769 is a prime.

It is a super-2 number, since 2×1218671281² = 2970319382268361922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1218671281.

It is not a weakly prime, because it can be changed into another prime (1218671291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609335640 + 609335641.

It is an arithmetic number, because the mean of its divisors is an integer number (609335641).

Almost surely, 2^1218671281 is an apocalyptic number.

It is an amenable number.

1218671281 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218671281 is an equidigital number, since it uses as much as digits as its factorization.

1218671281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 37.

The square root of 1218671281 is about 34909.4726542811. The cubic root of 1218671281 is about 1068.1416723622.

The spelling of 1218671281 in words is "one billion, two hundred eighteen million, six hundred seventy-one thousand, two hundred eighty-one".