18561406 has 4 divisors (see below), whose sum is σ = 27842112. Its totient is φ = 9280702.

The previous prime is 18561401. The next prime is 18561407. The reversal of 18561406 is 60416581.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18561401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4640350 + ... + 4640353.

It is an arithmetic number, because the mean of its divisors is an integer number (6960528).

Almost surely, 2^18561406 is an apocalyptic number.

18561406 is a deficient number, since it is larger than the sum of its proper divisors (9280706).

18561406 is an equidigital number, since it uses as much as digits as its factorization.

18561406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9280705.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 18561406 is about 4308.2950223958. The cubic root of 18561406 is about 264.7709234296.

Adding to 18561406 its reverse (60416581), we get a palindrome (78977987).

It can be divided in two parts, 1856140 and 6, that multiplied together give a triangular number (11136840 = T₄₇₁₉).

The spelling of 18561406 in words is "eighteen million, five hundred sixty-one thousand, four hundred six".