18561407 has 2 divisors, whose sum is σ = 18561408. Its totient is φ = 18561406.

The previous prime is 18561401. The next prime is 18561409. The reversal of 18561407 is 70416581.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18561407 - 2²⁴ = 1784191 is a prime.

Together with 18561409, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18561401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9280703 + 9280704.

It is an arithmetic number, because the mean of its divisors is an integer number (9280704).

Almost surely, 2^18561407 is an apocalyptic number.

18561407 is a deficient number, since it is larger than the sum of its proper divisors (1).

18561407 is an equidigital number, since it uses as much as digits as its factorization.

18561407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 18561407 is about 4308.2951384509. The cubic root of 18561407 is about 264.7709281845.

Adding to 18561407 its reverse (70416581), we get a palindrome (88977988).

The spelling of 18561407 in words is "eighteen million, five hundred sixty-one thousand, four hundred seven".