18244421 has 4 divisors (see below), whose sum is σ = 19647852. Its totient is φ = 16840992.

The previous prime is 18244411. The next prime is 18244433. The reversal of 18244421 is 12444281.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8702500 + 9541921 = 2950^2 + 3089^2 .

It is a cyclic number.

It is not a de Polignac number, because 18244421 - 2²² = 14050117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18244411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 701696 + ... + 701721.

It is an arithmetic number, because the mean of its divisors is an integer number (4911963).

Almost surely, 2^18244421 is an apocalyptic number.

It is an amenable number.

18244421 is a deficient number, since it is larger than the sum of its proper divisors (1403431).

18244421 is a wasteful number, since it uses less digits than its factorization.

18244421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1403430.

The product of its digits is 2048, while the sum is 26.

The square root of 18244421 is about 4271.3488501877. The cubic root of 18244421 is about 263.2550403718.

The spelling of 18244421 in words is "eighteen million, two hundred forty-four thousand, four hundred twenty-one".