1218735797 has 4 divisors (see below), whose sum is σ = 1290426156. Its totient is φ = 1147045440.

The previous prime is 1218735781. The next prime is 1218735811. The reversal of 1218735797 is 7975378121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7975378121 = 97 ⋅82220393.

It can be written as a sum of positive squares in 2 ways, for example, as 828633796 + 390102001 = 28786^2 + 19751^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218735797 - 2⁴ = 1218735781 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218735757) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35845154 + ... + 35845187.

It is an arithmetic number, because the mean of its divisors is an integer number (322606539).

Almost surely, 2^1218735797 is an apocalyptic number.

1218735797 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1218735797 is a deficient number, since it is larger than the sum of its proper divisors (71690359).

1218735797 is an equidigital number, since it uses as much as digits as its factorization.

1218735797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71690358.

The product of its digits is 740880, while the sum is 50.

The square root of 1218735797 is about 34910.3966892386. The cubic root of 1218735797 is about 1068.1605210360.

The spelling of 1218735797 in words is "one billion, two hundred eighteen million, seven hundred thirty-five thousand, seven hundred ninety-seven".