21145303453 has 4 divisors (see below), whose sum is σ = 21827410048. Its totient is φ = 20463196860.

The previous prime is 21145303441. The next prime is 21145303489. The reversal of 21145303453 is 35430354112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21145303453 - 2¹³ = 21145295261 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 682106563 = 21145303453 / (2 + 1 + 1 + 4 + 5 + 3 + 0 + 3 + 4 + 5 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145303423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 341053251 + ... + 341053312.

It is an arithmetic number, because the mean of its divisors is an integer number (5456852512).

Almost surely, 2^21145303453 is an apocalyptic number.

It is an amenable number.

21145303453 is a deficient number, since it is larger than the sum of its proper divisors (682106595).

21145303453 is an equidigital number, since it uses as much as digits as its factorization.

21145303453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 682106594.

The product of its (nonzero) digits is 21600, while the sum is 31.

Adding to 21145303453 its reverse (35430354112), we get a palindrome (56575657565).

The spelling of 21145303453 in words is "twenty-one billion, one hundred forty-five million, three hundred three thousand, four hundred fifty-three".