21453125 has 14 divisors (see below), whose sum is σ = 26835594. Its totient is φ = 17150000.

The previous prime is 21453119. The next prime is 21453143. The reversal of 21453125 is 52135412.

It can be written as a sum of positive squares in 7 ways, for example, as 19509889 + 1943236 = 4417^2 + 1394^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21453125 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21453125.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 14939 + ... + 16311.

Almost surely, 2^21453125 is an apocalyptic number.

21453125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21453125 is a deficient number, since it is larger than the sum of its proper divisors (5382469).

21453125 is an frugal number, since it uses more digits than its factorization.

21453125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1403 (or 1378 counting only the distinct ones).

The product of its digits is 1200, while the sum is 23.

The square root of 21453125 is about 4631.7518284122. The cubic root of 21453125 is about 277.8626592450.

Adding to 21453125 its reverse (52135412), we get a palindrome (73588537).

The spelling of 21453125 in words is "twenty-one million, four hundred fifty-three thousand, one hundred twenty-five".