18408961 has 4 divisors (see below), whose sum is σ = 18435924. Its totient is φ = 18382000.

The previous prime is 18408953. The next prime is 18408979. The reversal of 18408961 is 16980481.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16980481 = 7 ⋅2425783.

It can be written as a sum of positive squares in 2 ways, for example, as 6471936 + 11937025 = 2544^2 + 3455^2 .

It is a cyclic number.

It is not a de Polignac number, because 18408961 - 2³ = 18408953 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18408961.

It is not an unprimeable number, because it can be changed into a prime (18408941) 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, 12430 + ... + 13831.

It is an arithmetic number, because the mean of its divisors is an integer number (4608981).

Almost surely, 2^18408961 is an apocalyptic number.

It is an amenable number.

18408961 is a deficient number, since it is larger than the sum of its proper divisors (26963).

18408961 is an equidigital number, since it uses as much as digits as its factorization.

18408961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26962.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 18408961 is about 4290.5665127113. The cubic root of 18408961 is about 264.0440745590.

It can be divided in two parts, 1840 and 8961, that added together give a palindrome (10801).

The spelling of 18408961 in words is "eighteen million, four hundred eight thousand, nine hundred sixty-one".