1218253493 has 2 divisors, whose sum is σ = 1218253494. Its totient is φ = 1218253492.

The previous prime is 1218253481. The next prime is 1218253501. The reversal of 1218253493 is 3943528121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 807866929 + 410386564 = 28423^2 + 20258^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218253493 - 2²⁰ = 1217204917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1218253193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609126746 + 609126747.

It is an arithmetic number, because the mean of its divisors is an integer number (609126747).

Almost surely, 2^1218253493 is an apocalyptic number.

It is an amenable number.

1218253493 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218253493 is an equidigital number, since it uses as much as digits as its factorization.

1218253493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 38.

The square root of 1218253493 is about 34903.4882640690. The cubic root of 1218253493 is about 1068.0195973927.

The spelling of 1218253493 in words is "one billion, two hundred eighteen million, two hundred fifty-three thousand, four hundred ninety-three".