18561408 has 32 divisors (see below), whose sum is σ = 49304760. Its totient is φ = 6187008.

The previous prime is 18561407. The next prime is 18561409. The reversal of 18561408 is 80416581.

It is an interprime number because it is at equal distance from previous prime (18561407) and next prime (18561409).

It is a tau number, because it is divible by the number of its divisors (32).

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 in 3 ways as a sum of consecutive naturals, for example, 23785 + ... + 24552.

Almost surely, 2^18561408 is an apocalyptic number.

It is an amenable number.

18561408 is an abundant number, since it is smaller than the sum of its proper divisors (30743352).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18561408 is an equidigital number, since it uses as much as digits as its factorization.

18561408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48354 (or 48342 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 33.

The square root of 18561408 is about 4308.2952545061. The cubic root of 18561408 is about 264.7709329394.

Adding to 18561408 its reverse (80416581), we get a palindrome (98977989).

The spelling of 18561408 in words is "eighteen million, five hundred sixty-one thousand, four hundred eight".