1218660731 has 2 divisors, whose sum is σ = 1218660732. Its totient is φ = 1218660730.

The previous prime is 1218660637. The next prime is 1218660739. The reversal of 1218660731 is 1370668121.

It is a strong prime.

It is an emirp because it is prime and its reverse (1370668121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1218660731 - 2¹⁴ = 1218644347 is a prime.

It is a super-2 number, since 2×1218660731² = 2970267954562908722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1218660691 and 1218660700.

It is not a weakly prime, because it can be changed into another prime (1218660739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609330365 + 609330366.

It is an arithmetic number, because the mean of its divisors is an integer number (609330366).

Almost surely, 2^1218660731 is an apocalyptic number.

1218660731 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218660731 is an equidigital number, since it uses as much as digits as its factorization.

1218660731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 1218660731 is about 34909.3215488356. The cubic root of 1218660731 is about 1068.1385900634.

The spelling of 1218660731 in words is "one billion, two hundred eighteen million, six hundred sixty thousand, seven hundred thirty-one".