18861331 has 2 divisors, whose sum is σ = 18861332. Its totient is φ = 18861330.

The previous prime is 18861307. The next prime is 18861341. The reversal of 18861331 is 13316881.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18861331 - 2⁹ = 18860819 is a prime.

It is a super-2 number, since 2×18861331² = 711499614183122, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18861293 and 18861302.

It is not a weakly prime, because it can be changed into another prime (18861301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9430665 + 9430666.

It is an arithmetic number, because the mean of its divisors is an integer number (9430666).

Almost surely, 2^18861331 is an apocalyptic number.

18861331 is a deficient number, since it is larger than the sum of its proper divisors (1).

18861331 is an equidigital number, since it uses as much as digits as its factorization.

18861331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 31.

The square root of 18861331 is about 4342.9633892079. The cubic root of 18861331 is about 266.1894132091.

The spelling of 18861331 in words is "eighteen million, eight hundred sixty-one thousand, three hundred thirty-one".