21724125 has 32 divisors (see below), whose sum is σ = 38064000. Its totient is φ = 10972800.

The previous prime is 21724111. The next prime is 21724133. The reversal of 21724125 is 52142712.

It is not a de Polignac number, because 21724125 - 2¹⁰ = 21723101 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21724095 and 21724104.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5601 + ... + 8649.

It is an arithmetic number, because the mean of its divisors is an integer number (1189500).

Almost surely, 2^21724125 is an apocalyptic number.

21724125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21724125 is a deficient number, since it is larger than the sum of its proper divisors (16339875).

21724125 is a wasteful number, since it uses less digits than its factorization.

21724125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3086 (or 3076 counting only the distinct ones).

The product of its digits is 1120, while the sum is 24.

The square root of 21724125 is about 4660.9146098164. The cubic root of 21724125 is about 279.0277718016.

Adding to 21724125 its reverse (52142712), we get a palindrome (73866837).

It can be divided in two parts, 217 and 24125, that added together give a palindrome (24342).

The spelling of 21724125 in words is "twenty-one million, seven hundred twenty-four thousand, one hundred twenty-five".