21479453 has 4 divisors (see below), whose sum is σ = 21532380. Its totient is φ = 21426528.

The previous prime is 21479441. The next prime is 21479467. The reversal of 21479453 is 35497412.

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 15194404 + 6285049 = 3898^2 + 2507^2 .

It is a cyclic number.

It is not a de Polignac number, because 21479453 - 2¹² = 21475357 is a prime.

It is a super-2 number, since 2×21479453² = 922733802358418, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21472453) 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, 25850 + ... + 26667.

It is an arithmetic number, because the mean of its divisors is an integer number (5383095).

Almost surely, 2^21479453 is an apocalyptic number.

It is an amenable number.

21479453 is a deficient number, since it is larger than the sum of its proper divisors (52927).

21479453 is an equidigital number, since it uses as much as digits as its factorization.

21479453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52926.

The product of its digits is 30240, while the sum is 35.

The square root of 21479453 is about 4634.5930781461. The cubic root of 21479453 is about 277.9762802597.

The spelling of 21479453 in words is "twenty-one million, four hundred seventy-nine thousand, four hundred fifty-three".