21320453 has 16 divisors (see below), whose sum is σ = 26952576. Its totient is φ = 16381440.

The previous prime is 21320447. The next prime is 21320479. The reversal of 21320453 is 35402312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21320453 - 2⁸ = 21320197 is a prime.

It is a super-2 number, since 2×21320453² = 909123432250418, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21320053) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3725 + ... + 7517.

It is an arithmetic number, because the mean of its divisors is an integer number (1684536).

Almost surely, 2^21320453 is an apocalyptic number.

It is an amenable number.

21320453 is a deficient number, since it is larger than the sum of its proper divisors (5632123).

21320453 is a wasteful number, since it uses less digits than its factorization.

21320453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3884.

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 21320453 is about 4617.4076060058. The cubic root of 21320453 is about 277.2886814759.

Adding to 21320453 its reverse (35402312), we get a palindrome (56722765).

The spelling of 21320453 in words is "twenty-one million, three hundred twenty thousand, four hundred fifty-three".