18780001 has 2 divisors, whose sum is σ = 18780002. Its totient is φ = 18780000.

The previous prime is 18779993. The next prime is 18780011. The reversal of 18780001 is 10008781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13512976 + 5267025 = 3676^2 + 2295^2 .

It is an emirp because it is prime and its reverse (10008781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18780001 - 2³ = 18779993 is a prime.

It is not a weakly prime, because it can be changed into another prime (18780011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9390000 + 9390001.

It is an arithmetic number, because the mean of its divisors is an integer number (9390001).

Almost surely, 2^18780001 is an apocalyptic number.

It is an amenable number.

18780001 is a deficient number, since it is larger than the sum of its proper divisors (1).

18780001 is an equidigital number, since it uses as much as digits as its factorization.

18780001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 448, while the sum is 25.

The square root of 18780001 is about 4333.5898513819. The cubic root of 18780001 is about 265.8062593230.

Adding to 18780001 its reverse (10008781), we get a palindrome (28788782).

The spelling of 18780001 in words is "eighteen million, seven hundred eighty thousand, one".