1218420681 has 8 divisors (see below), whose sum is σ = 1640333760. Its totient is φ = 804394032.

The previous prime is 1218420677. The next prime is 1218420691. The reversal of 1218420681 is 1860248121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1218420681 - 2² = 1218420677 is a prime.

It is a super-2 number, since 2×1218420681² = 2969097911777007522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1218420641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1971246 + ... + 1971863.

It is an arithmetic number, because the mean of its divisors is an integer number (205041720).

Almost surely, 2^1218420681 is an apocalyptic number.

It is an amenable number.

1218420681 is a deficient number, since it is larger than the sum of its proper divisors (421913079).

1218420681 is a wasteful number, since it uses less digits than its factorization.

1218420681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3943215.

The product of its (nonzero) digits is 6144, while the sum is 33.

The square root of 1218420681 is about 34905.8831860762. The cubic root of 1218420681 is about 1068.0684520014.

The spelling of 1218420681 in words is "one billion, two hundred eighteen million, four hundred twenty thousand, six hundred eighty-one".