21553454 has 16 divisors (see below), whose sum is σ = 35668080. Its totient is φ = 9704640.

The previous prime is 21553453. The next prime is 21553459. The reversal of 21553454 is 45435512.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21553453) 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 7 ways as a sum of consecutive naturals, for example, 9044 + ... + 11175.

It is an arithmetic number, because the mean of its divisors is an integer number (2229255).

Almost surely, 2^21553454 is an apocalyptic number.

21553454 is a deficient number, since it is larger than the sum of its proper divisors (14114626).

21553454 is a wasteful number, since it uses less digits than its factorization.

21553454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20275.

The product of its digits is 12000, while the sum is 29.

The square root of 21553454 is about 4642.5697625345. The cubic root of 21553454 is about 278.2951422693.

Adding to 21553454 its reverse (45435512), we get a palindrome (66988966).

The spelling of 21553454 in words is "twenty-one million, five hundred fifty-three thousand, four hundred fifty-four".