21453407 has 4 divisors (see below), whose sum is σ = 21547320. Its totient is φ = 21359496.

The previous prime is 21453401. The next prime is 21453427. The reversal of 21453407 is 70435412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21453407 - 2⁴ = 21453391 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 (21453401) 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, 46613 + ... + 47070.

It is an arithmetic number, because the mean of its divisors is an integer number (5386830).

Almost surely, 2^21453407 is an apocalyptic number.

21453407 is a deficient number, since it is larger than the sum of its proper divisors (93913).

21453407 is an equidigital number, since it uses as much as digits as its factorization.

21453407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93912.

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 21453407 is about 4631.7822703577. The cubic root of 21453407 is about 277.8638767355.

Adding to 21453407 its reverse (70435412), we get a palindrome (91888819).

The spelling of 21453407 in words is "twenty-one million, four hundred fifty-three thousand, four hundred seven".