21245523 has 8 divisors (see below), whose sum is σ = 30506448. Its totient is φ = 13074144.

The previous prime is 21245519. The next prime is 21245531. The reversal of 21245523 is 32554212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21245523 - 2² = 21245519 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21245493 and 21245502.

It is not an unprimeable number, because it can be changed into a prime (21245513) 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 7 ways as a sum of consecutive naturals, for example, 272340 + ... + 272417.

It is an arithmetic number, because the mean of its divisors is an integer number (3813306).

Almost surely, 2^21245523 is an apocalyptic number.

21245523 is a deficient number, since it is larger than the sum of its proper divisors (9260925).

21245523 is a wasteful number, since it uses less digits than its factorization.

21245523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544773.

The product of its digits is 2400, while the sum is 24.

The square root of 21245523 is about 4609.2866042371. The cubic root of 21245523 is about 276.9634596676.

Adding to 21245523 its reverse (32554212), we get a palindrome (53799735).

The spelling of 21245523 in words is "twenty-one million, two hundred forty-five thousand, five hundred twenty-three".