18961409 has 8 divisors (see below), whose sum is σ = 20544480. Its totient is φ = 17430336.

The previous prime is 18961403. The next prime is 18961417. The reversal of 18961409 is 90416981.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18961409 - 2⁸ = 18961153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18961403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12239 + ... + 13700.

It is an arithmetic number, because the mean of its divisors is an integer number (2568060).

Almost surely, 2^18961409 is an apocalyptic number.

It is an amenable number.

18961409 is a deficient number, since it is larger than the sum of its proper divisors (1583071).

18961409 is a wasteful number, since it uses less digits than its factorization.

18961409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25999.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 18961409 is about 4354.4700021931. The cubic root of 18961409 is about 266.6593822663.

The spelling of 18961409 in words is "eighteen million, nine hundred sixty-one thousand, four hundred nine".