1218556801 has 24 divisors (see below), whose sum is σ = 1544916672. Its totient is φ = 933739200.

The previous prime is 1218556789. The next prime is 1218556817. The reversal of 1218556801 is 1086558121.

It is not a de Polignac number, because 1218556801 - 2⁷ = 1218556673 is a prime.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1218556301) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 284391 + ... + 288643.

It is an arithmetic number, because the mean of its divisors is an integer number (64371528).

Almost surely, 2^1218556801 is an apocalyptic number.

1218556801 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1218556801 is a deficient number, since it is larger than the sum of its proper divisors (326359871).

1218556801 is an equidigital number, since it uses as much as digits as its factorization.

1218556801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4393 (or 4332 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 37.

The square root of 1218556801 is about 34907.8329462028. The cubic root of 1218556801 is about 1068.1082248172.

It can be divided in two parts, 12185 and 56801, that added together give a palindrome (68986).

The spelling of 1218556801 in words is "one billion, two hundred eighteen million, five hundred fifty-six thousand, eight hundred one".