1218561801 has 8 divisors (see below), whose sum is σ = 1624923360. Its totient is φ = 812287392.

The previous prime is 1218561797. The next prime is 1218561833. The reversal of 1218561801 is 1081658121.

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

It is not a de Polignac number, because 1218561801 - 2² = 1218561797 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1218561401) 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, 25510 + ... + 55568.

It is an arithmetic number, because the mean of its divisors is an integer number (203115420).

Almost surely, 2^1218561801 is an apocalyptic number.

It is an amenable number.

1218561801 is a deficient number, since it is larger than the sum of its proper divisors (406361559).

1218561801 is a wasteful number, since it uses less digits than its factorization.

1218561801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43575.

The product of its (nonzero) digits is 3840, while the sum is 33.

The square root of 1218561801 is about 34907.9045632934. The cubic root of 1218561801 is about 1068.1096857076.

The spelling of 1218561801 in words is "one billion, two hundred eighteen million, five hundred sixty-one thousand, eight hundred one".