1820218402 has 4 divisors (see below), whose sum is σ = 2730327606. Its totient is φ = 910109200.

The previous prime is 1820218399. The next prime is 1820218403. The reversal of 1820218402 is 2048120281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2048120281 = 1277 ⋅1603853.

It can be written as a sum of positive squares in only one way, i.e., 1804465441 + 15752961 = 42479^2 + 3969^2 .

It is not an unprimeable number, because it can be changed into a prime (1820218403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 455054599 + ... + 455054602.

Almost surely, 2^1820218402 is an apocalyptic number.

1820218402 is a deficient number, since it is larger than the sum of its proper divisors (910109204).

1820218402 is an equidigital number, since it uses as much as digits as its factorization.

1820218402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 910109203.

The product of its (nonzero) digits is 2048, while the sum is 28.

The square root of 1820218402 is about 42664.0176495369. The cubic root of 1820218402 is about 1220.9779854066.

Adding to 1820218402 its reverse (2048120281), we get a palindrome (3868338683).

The spelling of 1820218402 in words is "one billion, eight hundred twenty million, two hundred eighteen thousand, four hundred two".