1321840018 has 4 divisors (see below), whose sum is σ = 1982760030. Its totient is φ = 660920008.

The previous prime is 1321839997. The next prime is 1321840019. The reversal of 1321840018 is 8100481231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8100481231 = 29 ⋅279326939.

It can be written as a sum of positive squares in only one way, i.e., 1157564529 + 164275489 = 34023^2 + 12817^2 .

It is a super-2 number, since 2×1321840018² = 3494522066372480648, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1321840019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330460003 + ... + 330460006.

Almost surely, 2^1321840018 is an apocalyptic number.

1321840018 is a deficient number, since it is larger than the sum of its proper divisors (660920012).

1321840018 is an equidigital number, since it uses as much as digits as its factorization.

1321840018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 660920011.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 1321840018 is about 36357.1178450658. The cubic root of 1321840018 is about 1097.4707780162.

The spelling of 1321840018 in words is "one billion, three hundred twenty-one million, eight hundred forty thousand, eighteen".