18780397 has 4 divisors (see below), whose sum is σ = 19596960. Its totient is φ = 17963836.

The previous prime is 18780383. The next prime is 18780403. The reversal of 18780397 is 79308781.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18780397 - 2⁷ = 18780269 is a prime.

It is a super-2 number, since 2×18780397² = 705406622955218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18780347) 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 in 3 ways as a sum of consecutive naturals, for example, 408247 + ... + 408292.

It is an arithmetic number, because the mean of its divisors is an integer number (4899240).

Almost surely, 2^18780397 is an apocalyptic number.

It is an amenable number.

18780397 is a deficient number, since it is larger than the sum of its proper divisors (816563).

18780397 is an equidigital number, since it uses as much as digits as its factorization.

18780397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 816562.

The product of its (nonzero) digits is 84672, while the sum is 43.

The square root of 18780397 is about 4333.6355407441. The cubic root of 18780397 is about 265.8081275966.

The spelling of 18780397 in words is "eighteen million, seven hundred eighty thousand, three hundred ninety-seven".