18780331 has 2 divisors, whose sum is σ = 18780332. Its totient is φ = 18780330.

The previous prime is 18780329. The next prime is 18780347. The reversal of 18780331 is 13308781.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18780331 - 2¹ = 18780329 is a prime.

It is a super-2 number, since 2×18780331² = 705401664939122, which contains 22 as substring.

Together with 18780329, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 18780293 and 18780302.

It is not a weakly prime, because it can be changed into another prime (18780431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9390165 + 9390166.

It is an arithmetic number, because the mean of its divisors is an integer number (9390166).

Almost surely, 2^18780331 is an apocalyptic number.

18780331 is a deficient number, since it is larger than the sum of its proper divisors (1).

18780331 is an equidigital number, since it uses as much as digits as its factorization.

18780331 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 18780331 is about 4333.6279258838. The cubic root of 18780331 is about 265.8078162195.

The spelling of 18780331 in words is "eighteen million, seven hundred eighty thousand, three hundred thirty-one".