20405444 has 12 divisors (see below), whose sum is σ = 36941100. Its totient is φ = 9850848.

The previous prime is 20405443. The next prime is 20405459. The reversal of 20405444 is 44450402.

It can be written as a sum of positive squares in 2 ways, for example, as 3496900 + 16908544 = 1870^2 + 4112^2 .

It is not an unprimeable number, because it can be changed into a prime (20405443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87839 + ... + 88070.

It is an arithmetic number, because the mean of its divisors is an integer number (3078425).

Almost surely, 2^20405444 is an apocalyptic number.

It is an amenable number.

20405444 is a deficient number, since it is larger than the sum of its proper divisors (16535656).

20405444 is a wasteful number, since it uses less digits than its factorization.

20405444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175942 (or 175940 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 23.

The square root of 20405444 is about 4517.2385369825. The cubic root of 20405444 is about 273.2637452568.

Adding to 20405444 its reverse (44450402), we get a palindrome (64855846).

The spelling of 20405444 in words is "twenty million, four hundred five thousand, four hundred forty-four".