21457453 has 4 divisors (see below), whose sum is σ = 21511900. Its totient is φ = 21403008.

The previous prime is 21457433. The next prime is 21457463. The reversal of 21457453 is 35475412.

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 18645124 + 2812329 = 4318^2 + 1677^2 .

It is a cyclic number.

It is not a de Polignac number, because 21457453 - 2¹³ = 21449261 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 (21457433) 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, 26628 + ... + 27421.

It is an arithmetic number, because the mean of its divisors is an integer number (5377975).

Almost surely, 2^21457453 is an apocalyptic number.

It is an amenable number.

21457453 is a deficient number, since it is larger than the sum of its proper divisors (54447).

21457453 is an equidigital number, since it uses as much as digits as its factorization.

21457453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54446.

The product of its digits is 16800, while the sum is 31.

The square root of 21457453 is about 4632.2190146840. The cubic root of 21457453 is about 277.8813435273.

It can be divided in two parts, 2145 and 7453, that multiplied together give a triangular number (15986685 = T₅₆₅₄).

The spelling of 21457453 in words is "twenty-one million, four hundred fifty-seven thousand, four hundred fifty-three".