20453440 has 112 divisors (see below), whose sum is σ = 58228992. Its totient is φ = 6690816.

The previous prime is 20453437. The next prime is 20453453. The reversal of 20453440 is 4435402.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (112).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 51322 + ... + 51718.

Almost surely, 2^20453440 is an apocalyptic number.

20453440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20453440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29114496).

20453440 is an abundant number, since it is smaller than the sum of its proper divisors (37775552).

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

20453440 is a wasteful number, since it uses less digits than its factorization.

20453440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 444 (or 434 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 22.

The square root of 20453440 is about 4522.5479544168. The cubic root of 20453440 is about 273.4778269665.

Adding to 20453440 its reverse (4435402), we get a palindrome (24888842).

The spelling of 20453440 in words is "twenty million, four hundred fifty-three thousand, four hundred forty".