1218861307 has 4 divisors (see below), whose sum is σ = 1223604216. Its totient is φ = 1214118400.

The previous prime is 1218861283. The next prime is 1218861311. The reversal of 1218861307 is 7031688121.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1218861307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1218861337) 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, 2371069 + ... + 2371582.

It is an arithmetic number, because the mean of its divisors is an integer number (305901054).

Almost surely, 2^1218861307 is an apocalyptic number.

1218861307 is a deficient number, since it is larger than the sum of its proper divisors (4742909).

1218861307 is an equidigital number, since it uses as much as digits as its factorization.

1218861307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4742908.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 1218861307 is about 34912.1942449912. The cubic root of 1218861307 is about 1068.1971875077.

The spelling of 1218861307 in words is "one billion, two hundred eighteen million, eight hundred sixty-one thousand, three hundred seven".